This is the paradox of tolerance. We resolve the paradox your argument is describing by reframing our concept of tolerance. When viewed as a social contract or peace treaty, we are able to tolerate each other and can refuse to tolerate intolerance. Under tolerance as a social contract, everyone in society agrees to be tolerant. If one group, say fascists, choose to be intolerant to any other group, the fascists are no longer protected by the agreement.
Thus we can reject fascist intolerance and bigotry while still tolerating each other. We can reject hate speech and targeted life-threatening information campaigns against lifesaving medical treatments while still enjoying free speech.
Also, fascists are bad-faith actors. Bad-faith actors will attempt to undermine our institutions for their gain no matter what we do. So our efforts should instead go to preventing bad-faith actors like fascists from taking power.
This is the paradox of tolerance. We resolve the paradox your argument is describing by reframing our concept of tolerance. When viewed as a social contract or peace treaty, we are able to tolerate each other and can refuse to tolerate intolerance. Under tolerance as a social contract, everyone in society agrees to be tolerant. If one group, say fascists, choose to be intolerant to any other group, the fascists are no longer protected by the agreement.
Thus we can reject fascist intolerance and bigotry while still tolerating each other. We can reject hate speech and targeted life-threatening information campaigns against lifesaving medical treatments while still enjoying free speech.
Also, fascists are bad-faith actors. Bad-faith actors will attempt to undermine our institutions for their gain no matter what we do. So our efforts should instead go to preventing bad-faith actors like fascists from taking power.