People grow up and grow out of stuff, but people like having secret knowledge that is being "suppressed" by the mainstream and they'll cling to that forever. Nobody is coming to antivax or anti-climate change conclusions by sitting down, doing research, and reading textbooks. They see stupid facebook posts where somebody makes up a story about their kid being harassed/oppressed by doctors/teachers/everyone for being antivax, and they want to side with the underdog. Their stories are BS and fortunately most people know that.

Now what takes neonazis a step further is they say there's a conspiracy where "they" are trying to destroy them through any means possible and they need to be ready to fight. Nazis grew support 80 years ago because they invented stories of violence and oppression against them. If you really want to empower them today, give them documented threats of violence--they'll be grateful for you playing right into their hands.

Nazis were pretty solidly on the way out until the internet made them into a new boogieman. People who absolutely did not care about them or saw them as a joke started sympathizing. That's the first step to being persuaded. We managed to virtually eliminate anarchists by not giving them the time of day, and we can do it with nazis as well.