I could see social-media-ish websites not wanting those names to prevent impersonation. They'd be deciding if they want to risk friction when a big name joins the platform (@cocacola needs Coca-Cola to verify) or risk threats from that big names' legal department (when @cocacola gets registered by someone who just posts furry porn of their mascot bear). It could just set a flag to require the account to verify or be renamed.
You're right about the variations there. I did think about it but decided NOT to add that in this version (felt like over-complicating the process), which I've now come to understand IS a required criteria. Will work on improving this.
As for @cocacola — that's on me. I've not yet gotten to the bottom half of the list of categories here: https://docs.username.dev/reference/categories (need to work on "government" and below). "company" is listed there and I suspect "cocacola" should be covered there.
In hindsight, I should've reserved names that I'm showing in the flipping text of the hero title but I didn't want to game the system or make it seem more reliant than it currently is. Which, again, I'm learning is not so reliant to begin with anyway.
PS. Love the passion around the topic here. One thing that I'm happy about is getting the problem validated. It's not in my head, I'm not the only one experiencing it, this is real. AND I WILL SOLVE IT :)
I get the argument in theory, but then I'll just register coca-cola (which is available), cocacola_furry (which is available), C0CAC0LA (which is available), etc.
You're signing up to play a game you can't win preemptively IMO.
As an aside, cocacola is also "available", despite being listed as an example of what you don't want to allow on the homepage and presumably would be flagged as a reserved brand name handle by this service.