Not sure how to react to a neo-nazi book club at the local high school doing membership drives though. There are always going to be people, regardless of society's guidance and teachings, who are extra susceptible to that kind of shit.
I think free speech absolutism leads to tolerating the intolerant, which just doesn't work when you are dealing with imperfect primate neurological evolution. People experience the uncaring universe, and our brains struggle to identify the complex and nuanced systems at the root of strife, causing them to look for simpler answers (Jewish space lasers vs. incomprehensible market interactions that over-exploit delicate ecosystems causing droughts). Our brains are set up to tackle problems at smaller scales, and what better way than scapegoating can you reduce a root cause to be more manageable? Mental gymnastics only have to be done once.
You can educate most people to equip them to defeat neo-nazi rhetoric logically, but humans cannot be programmed with the right answers and society will always produce some fuck-ups. Is it easier to prevent a new member of a hate group by banning their ideas, or let them ruin an innocent life and attempt to rehab them after?