It's unethical if you believe that people should be free in expressing their opinions. (Yes, I know that freedom of speech in the US constitution concerns the government and not companies, but I'm talking about freedom of speech as a general value. I find it unethical to suppress someone's ability to freely voice their opinions regardless of whether the government or a private entity does it.)
> It's unethical if you believe that people should be free in expressing their opinions.
No it's not, because free speech does not equal the right to be heard.
> I find it unethical to suppress someone's ability to freely voice their opinions
Can you really not come up with a single example of when you feel a group, entity, corporation, whatever has any right to remove a person from their platform or premise because of what they are saying? Really? This is "unethical", categorically?