The way I heard the story everyone could say whatever they wanted on 4chan, but all the discussions were always "won" by the Nazis through better arguments and

The way I heard the story everyone could say whatever they wanted on 4chan, but all the discussions were always "won" by the Nazis through better arguments and facts, so everyone else got tired on always getting called out on their own delusions, so they left the place, where only reason and facts prevailed. Hence the necessity to ban them on other platforms, because of the impossibility to win arguments against them. The only way they could keep believing in their delusions (like "people are equal" etc.) was to create safe spaces where they could ban everyone disagreeing with them. Apparently in a truly free space Nazis win all arguments, which makes everyone else leave. The other explanation is "those people are mean and I don't want to hang around mean people", but that's really not all that different from the first explanation.