Ashton, I think the answer to your question is that the logic of all the arguments is sound, but the argument itself appears unsound because the premises are very open to being...false. So take yer favorite Ballmer argument for why it is important for the future of the U.S. economy that M$ preserve their monopoly. His argument is (usually...at least to smurfs from Business Schools) logical, but it doesn't start from true premises. Now if the true premises were,

M$ is the worst example of business excrement that has ever sucked a camel's
behind.

we'd surmise his argument was...well...Micro$peak. But he doesn't do this, he starts from "M$ owns your private parts." The conclusion is, do what we say. Yer basic Smurf thinks, damn, that's a true premise, I better not disturb the private parts I've given M$ for safekeeping. A disgusting example of Smurfdom, eh?

So when the Islamo-Fanaticist premises his argument by "Since Jews control...whatever it is we know they control", it appear stupid and non-logical. But the center of the argument can (sans any new "facts") be logical.

An alternate example is the Fundementalist argument that starts from, "Can we at least agree the World had a beginning?" Uh...okay. "And that God has spoken through the prophets (or is it profits)?" Uh...well...I'm a Christian...so yeah, I'll agree with that. "And that the Biblical prophets were divinely inspired?" Umm...well, it's hard to be a prophet if not divinely inspired. "But they have written that 'God created the world in yadda, yadda, yadda'". Hmmm...so, your religious beliefs have now be hijacked into something which violates a good deal of modern science.

The correct response should have been, "Who the hell are you to interpret God's message to the what might have been what the prophets have written, and you cannot even be sure they wrote it?" Premise wrong, learn science, stop putting your words in God's mouth...presuming you know which God you are putting your words into...and She might get damn pissed if you keep it up.