If Trump is a narcissitic fascist dictator (in the making) as alleged, why would he maintain a Twitter?

I thought about this when one of my pilot buddies mentioned that he trolls Trumps twitter all the time.

Think about it, one of the first things to go in an authoritarian society is comedy. Because that leadership won't allow itself to be criticized, and that is one of the primary targets of comedy.

So why would Trump keep a Twitter profile that would allow him to be trolled on a constant basis?