>>In the case of fascism - (capital-F and lower-case-f), it's already been demonstrated repeatedly (with great loss of life and material progress), that this kind of intolerance must be stopped early and often.
This is your political bias coming through I think. I assume you self identify as "left" as such you easily see the extreme harm that comes from fascism, but I bet you do not view communism and socialism as being equally dangerous. They are.
The danger to society however is not Fascism, but is Authoritarianism / Totalitarianism. That is what needs to be combated with arguments, and education. Fascism is a type of Totalitarianism, but lets identify the root cause of the problem and fight it. Lets oppose all forms of Authoritarian control over people, not just the economic "Right".
Education is really the key, an educated society generally, and naturally wants to have more liberty, they trend more libertarian. This is why one of the first things a Authoritarian society does is limit education to only those groups that the people in power believe will be loyal to their Authoritarian power structure.
My biggest issue with your comment is you have not defined what "shutting down fascism" looks like. You can only defeat (truly defeat) an oppressive dogmatic ideology like fascism with logic, reason, and education. You might be able to temporarily suppress it with guns, violence and "internet bulling" but all you are doing is covering up a festering wound.
Change your tacit, Oppose Authoritarianism, Support education (not schooling), support teaching people how to think critically, support rigorous debate.
DO NOT support censorship, curbing of freedom, violence (i.e Punch a Nazi), or even bullying, that will never defeat ideologies like Fascism, and in some ways to strengthen them