There's no legal grounds to sue for misnaming a company (or person for that matter). They probably just do it because Zuck and Musk are right wingers, the news is right wing and approves of both of them suppressing anything remotely left wing and promoting Nazi shit, so, there you have it. The owners tell the (also right wing) reporters and commentators to use the new names.

I don't personally give much of a fuck about Meta since it's more akin to Google -> Alphabet change. Google is still Google, just under Alphabet. Facebook is still Facebook. Like they didn't change the branding. The "X" thing is stupid as fuck though. Had he created X and said Twitter the overarching company is now X but Twitter is Twitter, ok, still childish because he's got an odd obsession with the letter, but whatever. But no he basically deleted Twitter's branding (which sold for $44B...the site itself could be replicated and essentially has been. The value is in the naming rights) and replaced it with a four-year-old's vision of "cool" with the X shit.