He hasn't stopped a lot of folks, including all the shitty ones that would normally be banned. Hell, he unbanned them in many cases (i.e. Trump.) With Blue he gave them a way to be all the top responses in comments no matter how shitty their take is. Making the feed useless can be just as bad (if not worse) then censoring it.
No. He may be influenced by others, but it's clear his ego is just that enormous and that his emotional immaturity makes him do stupid shit impulsively.
Even if he was 'manipulated' he would be the same person regardless if he wasn't. He is clearly a self-serving person with ego problems. There are no billionaires that aren't fucked up people.
How are you defining worth? It's value was probably in the 20Bs and it's market value was well in the 30Bs. By value I am saying a world where owners just dumped all their shares until they were no longer owners, by market value I mean what another entity might pay to buyout twitter.