I'm also suspicious -- what stops the aforementioned individuals from finding another website/forum? I seem to remember hearing that after Reddit closed down several of the more unsavory/flat-out-awful subreddits, a large contingent of those users moved to another site (can't remember which though).
FWIW, I support clamping down on hate speech, but only if it's accompanied by some form of education (otherwise, you're just hiding the problem).