Like how we're fighting in Egypt and Tunisia and Libya and Yemen now? I guess you're right I concede... oh... we're not fighting there? Yeah, it doesn't follow that influencing the rebellion at an earlier stage would inexorably lead to us fighting in the streets of Damascus. In fact, it would have made it virtually impossible. Now, since the Syrian crisis threatens to draw in our close allies Turkey, Jordan, and Israel, it's actually more likely than not that some sort of intervention will be forced on us down the road. This could have been avoided.
As for Israel, if your definition of pugnacious only includes interstate war where the very existence of the Jewish state is on the line then yes, they've been less so in recent years. But if you were like most people you'd include the attacks they've carried out inside Lebanon, Gaza, and Syria in just the last few years. Hell, in Syria they've bombed in just the last few months. If any other country had done the things Israel has you wouldn't hesitate for a minute to call it pugnacious. Again, no value judgement here. I happen to think that, on the whole, Israel is justified in what it does militarily. But it's unquestionably no less pugnacious now than it's been in the past. If anything it's more so under Netanyahu.