> a) Should twitter be allowed to cancel accounts who harm twitter?
Although some people agree that is the question, it is not the fundamental one here. Most of the respectable arguments are that Twitter's bans are senselessly harming Twitter. They're building a gaping hole in their offering that a competitor can cover.
Twitter doesn't compete in a free market segment. No upstart is going to come along and beat Twitter because they monopolize users' access to their own social networks (if you want to participate in conversations your friends are having, you can't do so from e.g. Mastodon because your friends almost certainly aren't on Mastodon).
The thing is, few other companies will do business with anyone trying to compete with Twitter. Parler was nuked. Gab was almost nuked, but they've managed to survive.
There's a huge demand for alternatives to Twitter, but other major tech companies, the corporate press, and many politicians are doing everything in their power to crush those alternatives and prevent them from springing up.
Huge demand is maybe an overstatement. A quick google search shows me that Parler had ~4 million active users a couple weeks ago. Twitter has >300 million. That’s about 1-2%. I don’t think that qualifies as huge.
There's a demand for service for narcissists, but it isn't huge. Twitter was becoming irrelevant and the only thing that brought Twitter back from irrelevancy was that POTUS was big user of it.
Although some people agree that is the question, it is not the fundamental one here. Most of the respectable arguments are that Twitter's bans are senselessly harming Twitter. They're building a gaping hole in their offering that a competitor can cover.