Here's the thing, how do you know who's going to be the next Hitler? You don't, which means you just ban someone on suspicion of harboring negative intent. Then, once that decision has been made, you ban supporters of those people. Then, you start banning people who sound like they might be supporters of those people. Then, you start banning people who other people have reported to be supporters of those kinds of people, based on no or little evidence.
Once the slope has slipped to this point, it's easy for a secret Fascist to get in control of the banning mechanism and start shutting down all descent. And suddenly, you have a Fascist shutting down everyone's free speech, and they rise unopposed to power. Then, once they've been in power for a while, they push the envelope farther, and eventually start killing their political rivals or people they label undesirable.
I'm not talking hypothetical examples here. That's ACTUALLY what we have observed happening on 5 separate occasions in the past. That exact progression. The first time, it was actually Communism Hitler was holding up as the threat you needed to ban speech for. Then, the 4 who rose to power afterward used Fascism as the thing they were saying they were banning before they got to power and started their mass extermination campaigns.
View attachment 3396
So, yeah, if you're about to argue slippery slope fallacy, it's hard to argue it's a fallacy when I can point to evidence of it having historically happened before and frequently and without variation. So, yes, literally. If you stop one person you fear will become the next Hitler from speaking, you REALLY ARE supporting another Hitler who will be different from the person you stopped the speech of.
It's kinda like the Twilight Zone episode where someone goes back in time to kill Hitler as a baby in his crib, and then the nanny goes and takes a baby from the Orphanage to replace him and that replacement turns out to be the one who actually became the Hitler who executed the Hollocaust. That's exactly the sort of scenario you get when you start shutting down people's free speech with accusations of fascism.
People at the time who were closer to the real events thought long and hard about these deep philosophical issues, and today we have forgotten those lessons. It really helps to look up the words and philosophical material from that time. There are some poigniant messages that are the real guide to how to prevent the next Hitler, and right now we are seriously failing and practically opening the door to usher the next one in here somewhere in the Western wold (and most likely the US, and at the rate things are going the next Hitler is going to be a Democrat specifically because it's the Democrats who are encouraging the Censorship.)