While you aren't wrong, I feel as if your looking at the minority of situations. While yes, such times do occur, and yes, sometimes there are people who act in the way you describe, however the majority of people don't feel this way, nor act this way. The majority will simply stop playing the game, either before, or after stating their opinion. If they stick with the game, its simply because they like the game because the pros outweigh the cons.
However, just because the pros outweigh the cons, does that mean I, or anyone else, cannot state what we believe is a con? I understand that this is not what you are saying, but in many cases, this is how people react. I also understand that my previous sarcasm may be contradictory, but in the vast majority of cases that I have stated my opinion, arguments are caused by people becoming aggressive towards myself, the opinion, or other people with the same opinion. I simply became sarcastic and aggressive because the person I was replying to was already objectively aggressive.
Saying something as simple as "I don't like female domination, I wish this character wasn't so dominant", is enough to piss people off and cause conflict. As people don't view this as a simple opinion, but will instead spin it and judge it as "this is the worst game ever made. The developer is a piece of shit and should kill themselves. Also, your mom gay". This, in my opinion, is the true issue with criticism. While yes, there are those who are objectively toxic. That said, there are an equal number of people who are just as toxic but on the opposite side of the spectrum and no one talks or complains about them.
Also, having a discussion about an opinion or criticism isn't inherently negative either. I like to think that this discussion has been fairly civil, and without toxicity. That said, discussions like this are the exception, not the expectation of when people actually state their criticism, especially when that criticism is deemed as "negative".