Out of all the things kids are exposed to and can access at a library or online, drag shows are basically a non-issue for two reasons: 1) they are, again, a very small niche that parents don't have to try very hard to avoid; 2) not teaching kids anything about conformity.
But taking your position in good faith, what else should we ban from public. Do clowns teach kids non-conformity? A kid in my elementary school wore a clown wig and cape to school every day for some reason, and kids bullied him.
What about Donald Trump? He repeatedly cheated on his wives, talks about how sexy his daughter is, got involved in fraudulent businesses, and then was elected president. Should we ban him from speaking publicly? That's a lot of non-conformity for kids to learn!