I'll briefly go over the three main points.
With regards to supporting the war, soldiers don't usually sign up to the forces to go into a particular war with another specific country; they sign up for a number of reasons and probably hope to be defending the rights and freedom of the many rather than aiding wars such as those in Iraq and Afghanistan.
In terms of murdering, I do agree with what you say, but you've got to bear in mind that again, people are signing up to defend the innocent. If you saw a group of kids kicking the living daylights out of an innocent bystander, you surely wouldn't see it such a bad thing to floor one of them to save the victim. It's considered by many to be an honourable thing to do, but of course, it's subjective.
Finally, when it comes to state assistance, the charity exists partly because the government isn't doing all it should to help and support those soldiers who are fighting or have fought in conflicts in terms of finance, social awareness, re-intergration into society, health and mental state. If the state were providing such support, then chances are, the charity wouldn't have nearly as much to do.