Think you need to look a little closer to home to be honest...
Of course a decision is made on a case by case basis where military action is authorised and where UK forces are engaged. It's the same for every other member of the United Nations, EU and NATO. The UK is not the only country with forces engaged or supporting in Libya (at last recollection it was USA, Canada, France, Canada, Norway, Italy, Denmark) so please don't try to paint some kind of ZOMG Cameron and Obama are bombing innocent Libyans for the oil rant.
Are you suggesting that as UK forces cannot realistically be deployed everywhere we should therefore intervene nowhere? Or that we should intervene in Syria without EU, UN or NATO authorisation? On the other hand if you are suggesting the UK adopts a policy of blanket isolationism and neutrality I can appreciate the argument although I think it's unrealistic and naive.
Having said that I respect you may just feel strongly that there are people in Syria who are dying that are deserving of our military support. So I'll ask you again. What is it exactly you've done to contribute to the situation in Syria?
Or is your plan to just sit at a keyboard wringing your hands criticising other peoples actions when you clearly haven't even taken the time to understand exactly what is happening beyond a headline or two?