Earlier quoted context omitted.
OK, Mill, On Liberty , chapter 2: > But I deny the right of the people to exercise such coercion, either by themselves or by their government. The power itself is illegitimate. The best government has no more title to it than the worst. It is as noxious, or more noxious, when exerted in accordance with public opinion, than when in or opposition to it. If all mankind minus one, were of one opinion, and only one person…
There's no philosopher you can't enlist in the support of any view if you quote them out of context (also: you could have done far better in finding a quote to deploy here; try searching On Liberty for the word "opinion"). The part you haven't come to yet is the Harm Principle.
Okay. So if we're preventing harm, then, what is the possible harm here? Do you think intolerant beliefs threaten society? I'm of the opinion that beliefs mean nothing until acted upon, that only intolerant actions threaten society.
Or to rephrase it as one of the core tenets of Silicon Valley, "Having a great idea is not enough. It is the manner in which ideas are executed that counts."[1]
1: https://news.ycombinator.com/item?id=2318849, linking to https://archive.is/U6C4l#selection-2043.104-2043.196