Yes, in part what I was saying that in some cultures, people are more openly critical. It just is accepted, and no one gets too offended unless they are from another culture. What you are saying about the inability in US/Canadian culture to be upwardly critical or even critical sideways is entirely true. It is also such a silly thing and really makes the workplace unpleasant for many people, more than someone calling my code shit might do.
As someone who grew up in multiple cultures and lived in other cultures (Toronto, Canada among a few others), I see all too clearly what it means to cross or run-up against cultural boundaries. I've had to explain to girlfriends (outside my culture) for instance not to get offended by my family (non-American) and the things they will say. Quickly, they come to realize that despite the sometimes harsh sounding words, culturally my very blunt family is much warmer than anything they encountered before.
I am also well aware of what criticism means in different cultures and workplaces and I do not struggle with what you described. Your advice about keeping all that in mind is solid from a practical perspective. What I am saying has nothing to do with advising or advocating people to be like Linus or like me. Rather I am saying a few important things - understand the value of bluntness, the reasons behind it, don't be harsh for the sake of being harsh, pretending is silly, and that I am a firm believer in honesty.
I do value knowing what the culture norms are, but I try not to let myself be entirely bound in life by them. I have worked long enough and put myself in situations not to work with people who make me play stupid games or diplomatic twister. People should not discount the value of being direct just because it is against their cultural norms. Further, they should see that people from other cultures or other mindsets might have another point of view worth considering. As a result of just being honest, I find in most situations my communication is perceived clearly. I know this because people tell me exactly that and the results seem to match.
There was an interesting article recently in the NYT or Washington Post or something else big about the UN Ambassador for Israel and what gets said to him from enemy countries behind close doors (nice things, blunt things) vs. the crazy rhetoric some of the same ambassadors use when addressing what he calls the "public UN." In part, one of the points he was making is that the real work was getting done behind closed doors and the rest was mindless gesturing and show for the people back home in various countries.
Regarding Linus specifically, what he says can be taken (and is) sometimes as harshness for the sake of it. That does not mean there is not passion, value, truth, and other things to be found. Notice though that the truly valuable things Linus says in harsh ways are nearly always backed up by facts. If Linus says someone's code is stupid, often he points out exactly why and where instead of wasting time trying to be diplomatic about a bad commit. Taking this to the extreme where you don't provide any reason, feedback, and facts is a big problem. People who do this are not being honest or blunt, they are just being jerks and there lies part of the difference.
Perception is important and that's something people forget. I get that people are sensitive, caught up in their culture, yet at some point I would advise people to think with their brains and grow up. People like to do the same thing I described in the UN - gesture using their status, position, titles. That is a dumb thing that stands in the way of getting things done and what many people would perceive as being a good person. If a CIO wanted to fire me because something I said hurt his/her feelings, that's fine with me and not a place I want to work. I would never purposely say hurtful things to someone, at least things that were not true and certainly not without a concrete reason. My view though is a bad prescription for many people, so it's important to also understand that.
It's also worth noting that there is a time and a place for criticism, which is not all the time. More often than not, instead of whining and blowing up at someone, the situation will correct itself if no one pretends or lies to provide encouragement otherwise. At some point you may need to still intervene, but it is contextual. I'll never tell someone who is doing a bad job a bunch of positive things to encourage them for the sake of it. Likewise, when they start doing an actual good job, I will thank them for it. Linus perhaps could use a little more positive reinforcement. I guess he's OK with how he is, so be it.
I am not afraid to sound insulting here by saying that I think it's a sign of low intelligence if you cannot step outside of yourself at times. Obviously it's hard to do this all the time. People really get so caught up in doing what is expected rather than thinking for themselves. This conjures notions of "sheeple" and living a false narrative. I find these things far more revolting than what anyone could say to me with simple words, other people believe otherwise. I learned long ago there is no way you can make everyone like you, but you can respect everyone at least on basic levels of behavior which does not necessarily mean bowing to their cultural norms and emotions, rather simple, basic humanity.
You mention some examples of social tap dancing. While doing consulting, I had to become the master of this and it's rather a necessary skill in this world that I hate. What people are doing by saying things like, "That doesn't look right to me" is usually lying by omission, acting passive aggressive, or simply communicating poorly by garbling the message. To be honest, this sometimes really annoyed me in Canada when people would pass-off passive aggressive behavior as "polite" behavior. Of course my own culture skews this perception and most of the time. My solution was to take my own advice - understand their point of view, don't be offended, and move forward to what's real.
Generally, I try to always provide facts, reasons, clarity, and to keep calm. I expect the same back, as it should be. I would rather live a good, honest life and not live in a fantasy world. One semi-effective test is that if you have to ask yourself if you are being an a-hole, you are the a-hole. Surprisingly, I have only actually yelled at anyone seriously once in my career and it was related to something just about anyone would react the same (racism). Being honest and blunt doesn't mean you have to treat people poorly, yell, or go out of your way to be negative. On the contrary, I tend to compliment people more because I am not afraid to be open.
I find being open breaks down a lot of important barriers at times. In my personal life, this often leads to a lot of "Thank yous" and being the go-to friend for advice, confessions, problems, and more. In the workplace, people feel comfortable bringing tough and embarrassing problems to me because they know they will get an honest and constructive answer. I often felt crippled at points in my career when I got polite, useless feedback. I can't express how many problems in life or programming I have solved by simply telling it like it is. Quite often, it has nothing to do with dropping f-bombs. Sometimes I just tell someone that I feel stupid and need help, and I am happy when others reciprocate. As you can see, this is probably one area where Linus and I differ, but I can't help but laugh at the reactions he gets from ridiculous people that don't want to admit their own faults. I have many faults and I freely admit them because I want help.
If I had to actually give a piece of advice here, it would be to just be yourself and figure out what you value. Everything you do should be working towards that. If someone stands in your way, don't run them over, just put yourself in a better position - find a new job, move, cut them off, be the better person, prove your points with facts, do whatever you need to get past it while staying a good person. Lying to yourself is a hard thing. Being critical is not being cynical, it is being honest if you approach it with a clear mind. This is all often at odds with tech culture and it has admittedly hurt me in a few cases. But I feel alright with myself and that is success for me.