You're confused. This has nothing to do with "free speech" rights. This is a confusion that many right-wingers seem to suffer from.
There's no "free speech" relevance when you act like an asshole, and people call you on it. It just means that you're being treated like an asshole should be treated.
Free speech also includes calling other who are being assholes out on being an asshole, and choosing not to associate with them.
One is entitled to say what they want. One is not entitled to a platform to say it on, nor are they entitled to not have consequences of saying those things.
Legally protected free speech is roughly as you describe. A platform built on providing free speech would be held to a different (higher?) standard. If twitter considers itself the latter would be a separate debate.
Morality as you define it. What's funny is how all the free speech supporters were so quiet when Milo was banned from speaking at CPAC. Nobody has any principles, it's all political.
You appear confused about what is "moral", as well. Let me give you a hint: defending politically-protected rights to anonymously criticize the government is moral, and defending hate speech is not moral.
Please don't complain about downvotes or make generalized claims about the community. Controversial and divisive threads are already on edge, so we have to take even more care to comment civilly and substantively.