I'm guessing that confusion is why musk thought it would be fine? In any case, it'll be a fucking payday for the lawyers of Meta, Microsoft, and Twitter as they get to spend the next few years battling over who actually owns the copyright.
Also, I've been using the site for a while, and after the "rebranding" happened, it took a surprisingly long time for things to change. For starters, I still had the bird logo on the main page long after the announcement. The favicon was still the bird until quite literally 5 minutes ago. And even now, the page title tag still says "Twitter". I've seen other people laugh about the login and register page still saying "join twitter!". It could be attributed to caching, of course, but I tried several tricks to clear my cache, and still I see "Twitter" everywhere. Hell, even surfing to "x.com" just redirects you to... twitter.com.
And of course, the Android app is still untouched. The description has been updated to say developed by "X corp." but the title of the app is still just... Twitter. The blue bird logo is also still all over the app.
Look, I've been a part of a few rebrandings. I know that it's a bitch, and that there are way more references to the old name than you'd expect. It takes a lot of planning, effort, and manpower to get this done right. But... even something as obvious as the page title? Or the redirect? That's basic stuff, man. It makes me wonder if musky just put a few interns on it, thinking it would be as easy as merely doing a quick find/replace.