The only reason I can think of for doing this is treason.
The CIA might not be on the same page as the president.
How can you have a pan-Arab Caliphate if Assad is still in power? The Obamatollah needs him gone.
Yup, wanted another Al-Qaeda and got it. Just another way to follow his beliefs as heard in church, from mentors, in college, and by his many parents.
It always depends on which rebels, which regime, and how they are led.
It worked against the Taliban, swimmingly. We used Special Forces guys to coordinate and help lead them.
It worked during the “surge” in Iraq, again because the US military helped to lead and coordinate them.
It worked against the Sandanistas in Nicaragua despite every attempt by the Democrats to cut the legs out from under them.
Arm a bunch of muslim jihadists and let them lead themselves, though, and you may not like the result. Unless you are a Turk, a Saud, or Obama. Then you just have the collateral PR damage to contend with.
Our own armed forces complain of lacking resources, but Barry always has a little (or a lot) for “rebel muslims”.