Syria sponsored the bastards who murdered my brothers back in '83.
I find the prospect of killing large numbers of people distasteful just like you. Nobody who's actually had to take lives relishes the thought unless they're a criminal or a psycopath. But, I don't see any other way wrt Syria.
Iran presents a different problem. Most average Iranians (who aren't arabs btw) hate their government. They'd probably stand up and cheer if a few cluster bomb laden cruise missiles hit their 'parliament' building while that madman was speaking. I've advocated dropping small handguns and VOA radios by the thousands to the Iranian student movement. Once they've got handguns, pretty soon they'll have rifles..then machine guns...then by God you've got a revolution with some teeth.
So for Syria we send a couple of armored divisions rolling towards Damascus killing anything that resists.
For Iran we do everything we can to foment an internal rebellion and this time we see it through.
L