It's a tough call sometimes. Or it feels like it. I didn't care for the site. Took too long to show what it was about so I closed the tab. Just a bit too cute for my taste.
I was going to post a comment about it, mainly as a data point, in case such things matter to the site owner. OTOH I have on iPhone and I don't have a Mac I use often enough to care about this sort of product anyway; it's in perpetual sleep mode 99% of the time. I'm not the target audience.
Does mentioning my dislike for the site make me negative? Is it to the long-term good that people feel reluctant to offer criticism?
I do get the point about "Knock stuff to show your IQ"; it's unpleasant and an easy habit to fall into. I've been with groups of geeks where it's impossible to discuss almost any piece of software because it turns into a dick measuring contest. (So to speak.)
Still, sometimes some things really are flawed and those flaws are worth pointing out.
I suppose that every criticism should be accompanied by some suggestion on how to fix or improve things, but that's not always possible.
I don't have any really good suggestions on how to temper negativity other than to encourage people to pause and consider why they are posting something, and for others to try to ignore the posts that irk them.