Earlier quoted context omitted.
> it has certainly made me be more careful in the comments I've made. Isn't this the ultimate form of groupthink?
Often times the people complaining about groupthink are also the ones acting immature. If you inject in your comment the feel of someone trying to rebel ("I know I'm going to get down voted..." or "I hate to be that guy..."), you're already starting off wrong. Act the part of an adult and you'll be treated like one. I've found that if I spend a few minutes to justify my belief, and approach the discussion as that of…
Not everytime though. Especially in topics like Microsoft/Apple/Google, the moderation is brutal if you don't fit in the groupthink.
A big example: http://winsupersite.com is hellbanned on HN from being submitted as a story(if you do it will show up for you, but actually it's killed so won't show up for others at all). What crime could the site have possibly committed to deserve such an extreme banning(there are no instances of other tech sites that I know of getting banned, can you give me any?).
Post complaining about the banning: http://news.ycombinator.com/item?id=3408883
The answer is simple, the site is of Microsoft watcher, insider and enthusiast Paul Thurrott who posts breaking news, analysis and reviews with a sometimes positive slant. That is enough for some "enthusiasts" of other platforms here to flag it to death and ultimately to hellbanning. I am guessing someone who innocently submits stories from there regularly will get their account hellbanned to, for not conforming to the groupthink on here.
This is just the visible tip of the iceberg of the groupthink which downvotes comments and flags any legitimate news that doesn't conform.
You think the point in this post is just a figment of the author's imagination? http://news.ycombinator.com/item?id=3663447
Another example of legitimate news getting flagged to death:
How long before Winbeta is hellbanned from ever appearing on HN for being a Windows-centric news site?
Just because you haven't experienced this does not mean that others have not constantly been downvoted for their (non disrespectful) opinions. I believe that's behind their defensive "I know I am going to get downvoted..." lines.