The trap a lot of the left has fallen into is often defining genuine disagreement over their ideas as "racist", "fascist", or "bigotry". This keeps those ideas from being challenged and refined thus making them ultimately unconvincing. "Tolerance" itself is a very loose concept here that has come to mean mostly the same as "political agreement". There's also no mechanism that I can see for correcting this issue. In this frame, the bar for what constitutes "fascism" keeps getting lower such that even mainstream political positions from 10-15 years ago are being labelled as "fascist" in some circumstances.
None of this seems healthy for the future of left wing thought and is already leading to a backlash (one naturally being called "fascist").
It's not a trap the left falls into. If anything, the left is overzealous in internal tone policing, to the point where activists and organizers wish it would become less of a distraction. You have organizations and individuals of prominence in the US political sphere who are openly and actively try to promote bigoted and fascist talking points and implement them in government, often using long-debunked arguments or outright lies, and the people insisting that these ideas are not bigoted or fascist are either being duped or arguing in bad faith. I do not and will not attribute good faith to reactionary, white-supremacist, ultra-nationalist right-wing movements as we have in the US.
None of this seems healthy for the future of left wing thought and is already leading to a backlash (one naturally being called "fascist").