Not to take this too far beyond the intended point, but I can help but understand this as part of the way the content/attention economy works.
To use an example with some emotional distance, I kept up with the feminist blogosphere in the early to mid 2000s. It was visible in real time the way people moved into that 'overstatement of harm' and 'hyperbolic denouncement' form of expression. It goes like this: you need to post frequently to attract regular readers and earn ad revenue and/or clout. The content needs to suit the topic of your blog, be timely, and be of interest to your readers. Let's face it, it's not every day that someone publishes the literal Protocols of the Elders of Zion. And since historical analysis is less interesting than current events, you need to find things being published now. There are horrible, bigoted screeds being published, but often in specialised places. Even if it's on mainstream platforms, it's not in the places you hang out for fun, so you need to go seek it out. And it's genuinely awful to dive deep into right wing communities or ideologies; the stuff they write is upsetting and genuinely traumatising to read day in and day out.
So the blogger decides not to expose themselves to that stuff, but to find what they can in communities closer to home. Sure, it's not as extreme, but if you look at it through a particular lens and with an uncharitable read, it's still gesturing at the awful content you know is out there. Eventually (quite rapidly) all the things you are denouncing on your blog are edge cases and fuck ups from people within your own community. But since you know the genuinely beyond the pale shit is out there, and you need to keep people interested, you're denouncing it with the same level of vitriol you started out with.
Another issue is that actual right wing hate content is, often, frankly really weird. It often contains referents to ideas or cultural products that are well known within those communities but completely opaque to people outside. Right wing screeds can rarely be accused of brevity or coherence. You need to do a lot of legwork to unpack what it's actually saying to your audience. Plus, since it's often so culturally alien, it's kind of less interesting to your readers? They find it easier to grasp why something is important when it comes from people they see as part of their own community and is written in a language they understand. It's easier to handwave away right wing hate groups as niche and insignificant, because it's not like the people you interact with regularly actually believe any of those things (never mind that the people making legislation actually do, and are culturally closer to the screeds).
I see the hyperbolic focus on fanfiction, fanart, and milquetoast corporate products as the current expression of the same process. I'm also not really sure what can be done about it? Especially as, in the current moment, the niche right wing ideologies have broken containment and ramped up attacks in the mainstream. So people have a lot of understandable fear and vitriol. I also don't think flattening the scales of awfulness and bigotry helps much, but several decades in I'm at a bit of a loss.