Why aren't hate groups banned in the U.S.?

[Tekken_Guy]

First of all, freedom of speech. And think people are more concerned when the groups become physically violent rather than something else.

Also, there's no agreement on what a hate group is by the two wings. Liberals tend to go after white supremacists, homophobic Christian organizations, and anti-immigration groups. Conservatives tend to go after black, Hispanic, and Muslim groups and radical feminist organizations.