This is just the nature of customer service, man. Anyone who's ever worked in the industry knows what it's like. You deal with terrible customers all day and you shit-talk them off the clock, but you never do it to their face, or guess what? You're out of a job.
The only reason stuff like this feels worse is because online, either in forums or social media, you have thousands of people liking, retweeting, upvoting, whatever, these comments all at once, making it seem like it's bigger than it is. In reality, even in the case of people genuinely stepping over the line, it still represents a fraction of your total consumer base, and you have to always keep that in mind. Sure, it'd be nice if everyone could treat each other with a little more respect and tact, but it's part of being a professional that you're able to handle the people who clearly aren't giving you that. It makes it doubly worse when you write off all legitimate criticism as toxic when it's coming from people who, while sometimes over-emotional and crass with their words, aren't stepping over any lines.