When the "opinions" being aired discriminate against other people or could lead to an avoidable death from dangerous misinformation, it should not be allowed.

Deplatforming works. Yes, banned people will leave and try to congregate somewhere else - but it is better that they are removed, so that the impressionable and the vulnerable are not hurt by their bigotry or misinformation. Besides, how many people have you honestly seen have a core belief successfully challenged and changed on the internet?