I've done a bit of research via google. There seem to be suggestions that only a tenth of the aid is going to the people, or that, like you said the aid inevitably ends up in the hands of non-civilians, ie. the rebels or the military.
Whether that is true or not, I believe it's still worthwhile as it's going to be some aid that someone will otherwise not get. Secondly I also believe whatever shortcomings there are in the program, effort is being made to improve it so that aid is being distributed more effectively.
If aid is being given to combatants, to an extent that it does more harm than good then I will definitely cease my contributions. But I don't see any evidence of this. So it's just speculation at this stage - aid may or may not be misdirected. In the absence of convincing evidence either way, it's better to give rather than withhold simply because there's a possibility that things may go wrong. In any event I have a high degree of confidence that the UN will either not allow such a thing to happen or will work towards fixing it if it is happening. There's too many contributing governments counting on them to do this for them not to. It would seem completely at odds with the UN's objective, for them to unnecessarily prolong civilian suffering.
If there are better ways of distributing aid than via the United Nations I would be open to switching my dollars to them, but I am not aware of any such credible alternative.
I think it all comes down to trust. Do you trust the United Nations to do the right thing? I do. And I will continue to until I see evidence to the contrary.
