I am not sure what to do when faced the extreme anti feminism that I commonly find on the internet.

If these commenters are foolish enough to disparage and denigrate any political role to women generally, then do them a favor and flame them to a crisp. If that's not enough to drive them off your site, then feel free to ban them.

These are thinly-veiled attempts at intimidation which are reprehensible in the extreme, and will not be taken lightly by anyone who cares seriously about any kind of politics other than mere alignment to power and privilege--which is most everyone in this day and age. Especially so when coming from people of a Western male background--who are thus embedded in a complex power structure rife with systemic biases, which discriminates towards all kinds of minority groups.

Simply stated, you don't have to be nice to these people. Quite the opposite, in fact. Sometimes that's all they'll understand.