I would first like to say that I consider myself very liberal on many issues, although in the following paragraphs the opposite may seem true.
That said, I believe that you are caught in the same trap that many others on all sides of the political spectrum are in. You seem to say that because NATO did not enter into the struggle in a humanitarian capacity as the media alleges, that the action is therefore wrong despite the humanitarian effects that it does have.
I think it would be difficult to say that every account of civilian murder by Serbian military and police forces is propaganda by the US. There have been atrocities performed by the Serbs against innocent Kosovars, and it should not matter that they are the result of action by the KLA. There are definite ethical differences between killing those that are armed and are fighting and killing the unarmed and uninvolved. This is of course not to say that either are right, but simply that the former may be less wrong.
I hesitate to draw similarities to World War II, but I feel that I must. The US did not enter into the Second World War for humanitarian purposes, despite at least some knowledge of Hitler's actions. (By saying this, I do not intend to draw any parallels between Hitler and Milosevic, except that they are both responsible for the killing of innocents in conflicts resulting from the taking of liberties from another group). However, you would be hard pressed to find someone that would condemn the end of the Holocaust because the US used propaganda and entered the conflict with economic motivations.
Please feel free to respond. I would be delighted to entertain any ideas you may have.