Hes got his right to free speech, even if you (or I) happen to think its really fucking stupid speech
Which has absolutely nothing to do with posting on Slashdot, a privately owned and edited forum. The Corrupt people have the right to say whatever they want on their own site, but there's nothing in the First Amendment that requires Taco to use his resources to expand the reach of their message.
Don't get me wrong, part of what makes Slashdot worthwhile is that they don't delete posts or ban the crazies and trolls, but when was the last time you saw a goatse link on the front page? The editors have discretion over what goes on the front page of their site.
using the submitters political leanings as a reason for why we shouldn't have his article here is I think I very bad path to go down.
I agree. I would however suggest that the editors edit the submissions to remove links to corrupt.org.