Toleration does not moderate radicals: it incites them.
It is a common place that history does not repeat itself. As so often, this shibboleth panders to a partial truth. Indeed, history’s does not condemn us to bear its repeat performance. It is the ignorant that cause the past’s suffering to return to haunt us.
Memoirs, documentations, and grilled acquaintances tell a recurring story about the Holocaust. Survivors had an interesting response to the “but why did you not leave while you could”? Yes, they were well aware of antisemitism. They were also cognizant that, the National Socialists program promised their liquidation. As Islamists put it today, there was then, too, a stated will to “decapitate” the many that they disliked. The Nazi program –unlike that of the Bolsheviks- was not only not a secret but was even advertised to drum up support. There are contemporary movements that act analogously.