Yes, I understand every bit of that (and the "Arabs are bankrolling the environmentalists" claim has been around for a long time). But you left out the most important point. Where does the social/sexual radicalism of the Western Left fit in on islam's plans for a world "theocracy?"
I've said this so many times that I'm sure FReepers are getting tired of it, but it's like old-time professional wrestling. Two angles are running at one time, one against one set of "heels" and another against another set of "heels." Each heel claims to be the greatest of all time. If one heel team is foreign, the American heels never get mad or even notice it. If both heel teams are foreigners but come from different places (each boasting that wherever he comes from is "the best"), then they ignore each others boast and don't get offended. They confine themselves only to their feud with the "faces." The heels never feud among themselves, even though logically they should be feuding among themselves all the time.
One minute we are facing in "angle" where homosexuals are about to destroy religious expression. Conservatives fight back with defenses of religion and attacks on secularism. The next minute we shift to the other "angle," where radical moslems want to impose "theocracy" and outlaw criticisms of religion. Conservatives do a complete 180, suddenly defending enlightenment secularism even to the point of defending homosexuals, and scream bloody murder about how any law muzzling criticism of religion violates the First Amendment.
These two angles go on constantly. Their coexistence makes no sense. Moslems and homosexuals should not be even quasi-allies, yet they are. The homosexuals and moslems advance along each front against their enemies, yet never at any time seem to quarrel with each other.
Does my question make sense now?
Of course, it makes sense that jihadis and the domestic radicals should form an alliance.
The Arab expression is "the enemy of my enemy is my friend." The corresponding communist expression is "the end justifies the means."
The focus of both sides' animus is the US of A. Why wouldn't they cooperate -- against the interests of America?
Long-term, the jihadis doubtless view the left as candidates for beheading practice. The left, naively, views the jihadis as candidates for, at best, conversion or, at worst, employment as useful idiots.
In this context, it is also important to note that, nowadays, the commies are probably less "pro-communist" than they are virulently "anti-American". There is an unmistakable strain of nihilism in today's left.
As you point out, this does leave the religious right in the paradoxical position of appearing to defend the "seculars" against the "theocratics", then turn around and have to line up with the "theocratics" vs the "seculars". It would probably be more appropriate philosophically to simply stand squarely against both sides, without resorting to the defense of either.