As a society we need to redefine what a public space is.
Twitter isn't a public space. It is a privately owned platform.
Which doesn't necessarily mean that Twitter should be treated as a town square, because it's clearly something different to that. Similar sorts of concerns about the centrality of private spaces to public use led to PruneYard Shopping Center v. Robins, a California case allowing political activity at shopping centres against the wishes of the operator. That case hasn't been widely followed in other states and countries, though, probably for good reasons.