I know people who would read the post, agree with it, and then turn around and say "but Robots shouldn't be in D&D, and neither should Artificers". There are quite a few people that are still salty about Eberron.
I don't think anyone would truthfully, willingly admit that they disagree with this post. And there are also people that will say they agree with it but still try to gatekeep the hobby.
I agree. A major part of this is just the nature of the discussions happening online. More controversial posts will get more attention, and it will appear that unpopular opinions are actually popular (and vice-versa) just due to that fact. A thread that says something simple like "I like Gnomes" is almost definitely going to get less posts and reactions than one about how they dislike/hate them (or think they shouldn't be a part of the game). Which can be hard to remember sometimes, and certainly doesn't help make the online community feel less toxic.
Don't get me wrong, I don't completely hate the online D&D community. If I did, I wouldn't be active on this site. However, sometimes, the stuff that I ranted about in the OP happens and overwhelms the positive parts of the community.
It also kind of sucks when most of those angry comments about how other people are playing badwrongfun are almost always directed at your specific playstyle (optimizing/powergaming, mostly, but also the occasional Eberron-hater or person that declares everything after AD&D 2e as not being "true D&D").
I know this whole rant is like the world's smallest violin, but it still sucks.