Slippery slope is actually a kind of logical fallacy.
The author needs to prove that suppressing fascist speech actually has some kind of negative effect or that it leads to other kinds of speech being suppressed. You have to look at intent here to see whether the suppression will lead to a slippery slope. In this case, it's not about suppressing speech it's about removing people who act in bad faith.
On this forum we often suppress the speech of people we disagree with. And people get banned too. If we subscribe to the author's point of view, then why do we have moderation or shadowbanning in the first place?
The author needs to prove that suppressing fascist speech actually has some kind of negative effect or that it leads to other kinds of speech being suppressed. You have to look at intent here to see whether the suppression will lead to a slippery slope. In this case, it's not about suppressing speech it's about removing people who act in bad faith.
On this forum we often suppress the speech of people we disagree with. And people get banned too. If we subscribe to the author's point of view, then why do we have moderation or shadowbanning in the first place?