Because misanthropy, outrage, and trollishness are now the new normal in all areas of life, not just on the internet. It's just most prominent in online gaming discussions imo (present company excepted 99% of the time) because for some reason, gaming discussions have always incited enormous defensiveness and factionalism.
But yeah, it's everywhere. Look at the political climate. Look at any discussion, anywhere, about anything, online. It's disheartening and worrying, but there's little we can do about it sadly.
I also think the internet has changed how people communicate in not always healthy ways. It's cliche to say it, but interesting sociologically and psychologically, that people will say things to one another - and more pertinently, THINK In ways about one another - that they never would face to face.
The lack of nuance, social cues, body language, tone of voice etc. seems to make people online default to the worst possible, most defensive attitude toward absolutely everything anyone says. And the gamification of everything - likes, dislikes, followers, etc. trying to establish a digital presence - seems to encourage a territorial response in people. Like, this comment/webpage/account is my turf, and I want to get likes for it and if I get dislikes or people attack my turf, I have to defend it etc. (Not me personally, but it seems this dynamic happens constantly.)
I used to think the internet, because it connects the world, would be the greatest facilitator of better communication between different views and ideologies ever created. Now... I'm not so sure. Sometimes I fear it's fundamentally altering how people think about and empathize with one another.
There's a more benign, but still worrying, side to this too, though. Because it's mostly text on a screen, when people express concerns or criticisms of a thing/person/product/position/whatever, it gets default interpreted as an utter rejection or disdaining of its target, even if the reality is that there's a more nuanced opinion beneath the words that would read in person - because of tone of voice and other cues - more like, "I have these criticisms, but I'm not totally negative towards it either." Essentially, people just assume the worst, and then get defensive.
Second to lastly, some of it is also just that people are more conscious consumers now, and more aware of their own interests and needs, with many more options at their disposal. They also have more information about the history of a company and have more of an ability to play armchair analyst (and this happens with everything - people think they're authorities on everything now after reading about it for an hour on the internet) and so they're more cautious and wary and less willing to simply trust corporations whose job it is, ultimately, to extract money from them.
And lastly... while I dislike the word "entitled" and think it gets thrown around way too much... there is also just an element that we've all grown up for generations now without a world war, with declining rates of disease, longer life spans, supermarkets filled with prepackaged foods, and advanced technology at our fingertips and in our pockets that our ancestors couldn't even dream of in their wildest imaginings. In short... yeah, we're slightly spoiled and aren't always mindful of that or as grateful as we could be for what we have imo.
I think all of the above plays into the sense that everything is so damn contentious and filled with consternation and venom all the time online. But I also think that perception, likewise, is a product of us assuming the worst. I think things are actually less dire than we might assume based on the surface image it might give, again, because of the text on a screen + anonymity vs face to face dynamic.
For instance... I'm hyped as hell for Nintendo Switch and have one preordered. But I bet based on my lengthy posts about concerns I have about it, many would assume I must hate the thing and can never be satisfied. I think a lot of it is just that disconnect between thought, text, and real human interaction.