What could a single user instance possibly do to be defederated on a massive scale? And at that point, why not simply join another instance?

Yes, but by proxying your traffic via cloudflare your domain will point to their IP instead of yours directly.

Or maybe do a Reddit and make an NSFW-free version of all? It’s definitely not because I want to or anything but I’ve found most of my subscribed NSFW communities through the all feed so far.