It's not just gamers. The Internet has spawned a culture of "no consequences for letting your Id come out to play." If I walk up to Big Bad John, and call him a rude name, he will knock my teeth out. That's called "immediate negative feedback." Consequence immediately follows action. On the Internet (although this kind of thing predates the Internet. The Internet just commoditized it), this negative feedback loop is…
Big Bad John is a strawman, because if Big Bad John was abusing his children or beating his wife, I wouldn't confront him either. I'd call the police. It doesn't reflect at all the legitimacy or illegitimacy of the criticism.
Also, we should probably get over that pretense that anonymity ends brutal criticism. Plenty of people are happy to sign pretty brutal criticism, or even to make a brand out of it.
The thing that it's easy to do is to attack "haters" or "cynics" because they don't really exist. They're what happens when people define other people's motivations by the effect on them personally. Somebody hates me? They're a "hater." Somebody says that something I think will work will definitely not work? They're a "cynic" that doesn't believe anything can improve and hate people who have retained the ability to dream.
The same people leaving comments on this game encouraging the designers to kill themselves will agree completely with this reasoning, because it has very little content.