You attack ideas by suffocating them, not by repeating them. Children learn words by hearing them spoken. Nothing more needs to happen; the brain is quite good at drawing the intended implications out. To promote an idea, you need only put it in people's heads over and over again.
The major problem with hate speech laws is trying to separate propaganda from education or intellectual discussion from dogmatic bigotry. It is trivial to mask one as the other and vice versa. And while an honest and critical person can make a good distinction in narrow contexts, nobody has been able to do it effectively on a cultural scale.
