Blocking a jackass does not mean the jackass has been removed or told to correct their actions. Leaving these issues in addressed by blocking them still means that the person's post can still be viewed by the online non members that visit the site. It creates a bad overall image and can actually harm a community.

I agree with Hank. Report it and something may come of it, but if a mod tells them to pull their head in and they start mouthing you off, then I'm pretty sure they won't survive on the site for very long.