The weapons we drop aren't doing any good. We haven't done any good in Syria. The rebels (terrorists) have almost toppled the Assad Regime (Legitimate government, Assad was democratically elected twice)
And if Assad and the Russians left Syria today IS, Al-Qaeda, etc. would to some extent fight, and some extend agree on how to rule.
In spite of all the propaganda and rhetoric, Syria was nowhere near the worst place in the region in 2010.
Over a quarter of a million Syrians have lost their lives. Millions upon millions have fled the country. At this point, arming these rebels will (besides whatever they keep for later) cause them to die in battle along with Russian and Syrian solders.
We've turned Syria into a living hell, we should let the Russians help them restore order. Stop WWIII.