Tbh these really are low-usage features, I didn't know about any of them, aside from the snoovatars that I've always found stupid. So I don't think anyone could be pushed away from the site because of this.
OTOH, if they're low-usage, why remove them? Do they spend too much bandwidth, CPU, whatever??
It's usually better to not touch code that is working, it won't become "clean" just because you deactivate some stuff and if you do try to actually remove code (to "clean" things, whatever that means in a setting bigger than a small project), good luck not breaking anything.
Code that exists still needs to be updated and maintained. It interacts with the rest of the code. Sure you can leave it lying around, but at a certain point the technical debt is going to catch up to you.
Maybe you can afford this in your personal projects but I have yet to work at a company willing to invest in that. Sure, a conscientious developer might clean up things they’re working on, but old code usually gets ignored until the pain of keeping it gets too great, until someone is forced to do something about it
Oh, sure, I've been there. Am there. And Reddit may have gotten to that point with these features where maintenance costs overtook the costs of removing them.