If you're for the rebels, you're stoked. If you against the rebels, you're upset, but understand the humanitarian aid. After all, this was just light weapons, communication, vehicles, and medical supplies.
But if your government is using chemical weapons, and you know this beyond a shadow of a doubt, you should be all for outside intervention. It's easy to say I would be against chemical weapons usage even if I'm pro-existing government, as I'm not in that position. I'm pretty sure it'd change my opinion of where I stand, but I don't have to make that decision right now.
Nato supplied the rebels for more than two years through Turkey, Saudis and Qatar. All American weapons and gears. I'm sure US knew it and didn't say anything even if they didn't command the supplies, which I'm not sure about.