Well it's these guys job to weigh in all options, so that means they're just doing their job. But it would be a great humiliation for the US or any European country (France and the UK were also very vocal about Assad) to suddenly change its mind, start helping Assad and to line up behind Russia and Iran. Anyone doing that could shut up about the Middle East for the next 50 years, so I think it's extremely unlikely.
Don't forget that Assad released islamists from his jails when the civil war started in order to present it as a war of Assad vs terrorists. I find it very worrying that many are ready to fall into his trap, and equally worrying that many start running around like headless chickens as soon as they hear "islamists".
Also the real threat for the West are people who go to Syria to fight, go back to their country, stay under the radar for 10 years and suddenly blow up a bomb somewhere. But this is very likely to happen, whatever happens in Syria.
Edit:
I just read this article and I agree with the conclusion: