Following that logic, I support censoring/deplatforming fascists et al. because I want to hurt their ability to do fascism, not for some higher principle of striving towards a perfect, values-neutral marketplace of ideas. Speech is just another front on the plains of power.
See this bit of discussion: https://news.ycombinator.com/item?id=33375286
They still take these cases. (It is a bit complicated, individual ACLU chapters have a lot of autonomy, and they do not all agree with each other in all ways.)
So I see a substantial difference.
On one hand, you have lawyers from a nonprofit arguing in court that, while someone's views may be abhorrent, they are legal, and the principle matters more than the harm.
On the other, you have a for-profit entity tilting the landscape upon that speech rests, and as the raging debates about this stuff have shown, is difficult to distinguish profit from other motives.
Running a company with specific ideological priors looks a lot different to me than defending assholes for past speech on principle.
Granting, of course, Twitter goes beyond this. They ban all hate speech at all, no matter how limited it is, but they're a private platform, which gets to the real heart of the issue. Everyone that cares deeply about this who is in agreement with Elon's side and isn't just being petulant about having personally been banned seems to equate Twitter with some kind of true public square or some necessary platform that handicaps a political movement if it can't access it. I just don't see this. The public streets, the government itself, I have no choice but to use and participate in. Everyone has to. But I have never had a Twitter account, never visit the site, and seem to have gotten along fine like that for over 40 years. Trump got banned and is still likely to win his party's presidential nomination in two years. It hasn't materially impacted his ability to get his message out and reach followers at all. Everything Kanye says is still going to be on every headline in every news service in the country the same day, and if he releases an album, his fans will still know. He doesn't need Twitter. I just don't see how that isn't definitive proof that Twitter is not this true common carrier people seem to think it is. You don't need access to one specific private platform to be heard. They're not like an electric utility with a local monopoly that is truly your only option to access a critical service. Trump and Kanye were both well known with hoards of followers before Twitter ever existed, and people would still hang on their words if Twitter completely disappeared tomorrow.
No one can credibly deny that some speech is harmful. We'd all like to suppress some speech that we don't like, but the reason free speech advocates take the position they take (generally) is that once speech is prohibited the status quo regime will ban legitimate criticisms. So the good has to be accepted with the bad.
It's a tough issue. If I'm honest I favor censorship of views that I believe are harmful, but would object strenuously if my point of view is censored. I also think being called slurs, etc, is an unpleasant user experience, to say the least, so from a business perspective if nothing else I get why that is censored. Still, the censorship has gone too far in my view. We need to figure out a way to circle this square.