Anyone who says that fascist should have the right to form political parties and express their fascist beliefs because of freedom of speech is siding with the fascist, and I'm sure that they'll thank you for your service to their cause before they throw you in jail or worse.
The marketplace of ideas requires those who participate to do so in good faith. Fascism exploits the social contract of all for the benefit of few, violating the good faith principle.
We are not required to tolerate the existence of fascism on any level.