I notice that Tesseract is also one of those clients which allows you to preemptively ban someone from a community even if they're never made an appearance there, if that's one of those features you're looking for. I imagine this explains the how, albeit not the why, I'm apparently banned by default from a handful of communities I'm certain I've never visited on an instance I'd never even heard of until I noticed in my own modlog that I was banned from them.

Evidently including, and this is the only reason I bring it up, !tesseract@dubvee.org.

...I think I'll stick with Alexandrite for now.