If you've read the news in the past two years, which you clearly have, you'd know that Syrian Rebels are not some monolithic group. It doesn't make it right, but Assad blows and is quite possibly using chemical weapons. We are the most powerful nation in the world, we cannot just stand idly by as a hundred thousand people have died in a conflict that is people seeking freedom vs people seeking tyranny.
Also, we want to limit our military involvement because there is a trend where involvement in a regime change makes you a target for the opposition which creates a large amount of instability - which is the problem you're trying to solve in the first place.
That's why we should arm Syrian Rebels.
Personally, I don't want this country taking sides in any other country's civil war. Especially countries where both sides are likely to end up as religio-ideological enemies.
If "our" side wins, what have we gained? Not much, I think. If "our' side loses, we lose in the world's eyes no matter how bad things were before.
This view of mine has evolved pretty far from where it was in 1991. When Gulf War I ended without a "permanent" (regime-change) victory, I favored arming anti-Ba'athist and/or Kurdish rebels in Iraq, and (later) anti-Taliban "warlords" in Afghanistan. Now I see that the al-Malaki and Karzai governments are pretty much as unfriendly as ones they supplanted, and about the only benefit gained over the past dozen or so years is that al-Qaeda has been deprived of those two safe havens.
Phukkum today and Nookum if they get froggy later.
