I say this as someone whose political views, if you force them onto the left-right spectrum, probably end up about 80% toward the left. E.g. I've spent millions over the past several elections supporting the Democrats.
It used to be that censorship was something the right did, and free speech was something the left were in favor of. But over the last few decades, banning "problematic" ideas has become a huge component of left culture (http://paulgraham.com/heresy.html).
Plus tech companies in general, and especially Twitter, lean to the left. Imagine walking around Twitter pre-Covid. You'd find plenty of openly far-left employees. How many openly far-right employees would you find? I don't think you'd find any.
The combination of (a) the left's recent focus on banning heretical ideas, (b) the leftward lean of tech companies generally, and (c) the leftward lean of Twitter even among tech companies, means that right-wing speech is much more likely to get banned on Twitter than left.
That's why people on the far right keep starting lame Twitter alternatives. You don't see people on the far left doing that. They don't need to. They have Twitter."