The problem is that ideologies can’t ever really be truly eliminated. Once one is created, it will always be around forever so long as just one human retains knowledge of it.

I too am saddened by the amount of people that hold Nazi (or Nazi-like) ideals, but there is basically nothing you or I can do. Outside of constantly trying to talk to them and convincing them to change their mind, society cannot be rid of ideologies. Even if you outlaw it (which is true in many places already), they will simply go underground to grow in numbers for a later time. Even if you deport them all to an island, they will still exist with hatred to come back later. Even if you genocide all of them, other people will remain that question if those ideals are really good, and some may foolishly think they are and become new Nazis. Now all the genocided ones have become martyrs. Its a neverending game of Whack-A-Mole.