I mean, of course he should be allowed back on. And I will continue to utterly ignore him, the same as I have ever done.
The point about free speech, is that you only know it exists once you allow it for people whose views you find idiotic or abhorrent. Everyone likes to think only their side has common sense.
If he advocates for an actual crime, that is different. If he says go bomb someone's house or posts kiddie porn, etc burn him and ban him. But just because his views are stupid, crazy or even "dangerous!", he should have the same rights as everyone else to espouse them publicly.
If Twitter wants to be truly "neutral" then it cant deplatform people just because they dont agree with them.