The population at large, if they know what Twitter is at all, surely already know it is ruined, just as surely as they understand that Musk, despite his many abilities, is a capricious, petulant man-baby who is acting out.
Yes, he can. We're criticizing him for being an oligarch and a hypocrite, not calling for regulation or whining about the First Amendment rights of the UAW.
Removing the checkmark from the UAW's Twitter account is in no way regulating the institution itself. Musk even relented and put the checkmark back.
Don't get me wrong - the unchecked power of billionaires in a society converging towards military industrial oligarchy and centralized control of consensus reality through the media, full of easily controlled and manipulated voters pathologically afraid of effective government, is definitely a problem worth being afraid of. But this isn't an example of it. This is just another "rich babyman throws his toys out of the pram" moment for Musk.