One effect of the BP oil spill is that stories about the Tea Party are disappearing from cable news. This seems especially pertinent in the case of Fox News, which has done more to hype the Tea Party movement than anyone else. Why would Fox bail on the 'baggers?
Commenter vrdrew suggests the best reason I've heard yet:
[t]he Fox News folks are smart enough to recognize the unfortunate irony of a political protest whose most notable action was dumping a valuable commodity in the ocean probably isn't the best story to be telling these days.
And there you have it!