If you do lean the right in your political leanings, and you want to refute this you have two options...
Option 1. Say, no We definitely are smart enough to build a good bomb and kill lots of people. And you feed into their violent rightwing extremist mantra. And, they get to insinuate you're planning someting like this.
Option 2. Say nothing and and accept the crack that you're stupid.
PMSNBC believs they've won either way. According to a November 2008 poll, there's at least 52% of the idiot voting public that would believe it.
Makes sabotage of the oil rig even more plausible.