3. I think Obama and the State Department recognize the fractious religious/social divisions at play.
from the same article -
On Monday, Clinton designated Jabhat al-Nusra, or "the Support Front" in Arabic, a foreign terrorist organization. The move freezes any assets its members may have in U.S. jurisdictions and bars Americans from providing the group with material support. The designation is largely symbolic because the group is not thought to have holdings or support in the United States, but officials hope the penalties will encourage others to take similar action and discourage Syrians from joining.
That step was part of a package intended to help the leadership of the Syrian Opposition Council improve its standing and credibility as it pushes ahead with planning for a post-Assad future.
The administration took further action Tuesday against extremists on both sides, with the Treasury Department setting separate sanctions against two senior al-Nusra leaders and two militant groups operating under the control of the Syrian government. Two commanders of the pro-Assad shabiha force also were targeted.
"We will target the pro-Assad militias just as we will the terrorists who falsely cloak themselves in the flag of the legitimate opposition," said David S. Cohen, the department's sanctions chief.