The actual quote goes "... for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols." It seems relevant to ask whether that incitement to respond to arguments with force is actually happening or not, before invoking the paradox.
I would say yes. Haven't we seen journalists being harassed for asking pointed questions, when this kind of harassment results in death threats?
Those people we send to jail until they rehabilitate and can return to normal society where we don't do those things.