I'm talking every conflict this country has been in the last 40 years ... - you have a point. There have been unjust wars the US has been involved in and indiscipline of US soldiers. There should be criticism where it's due.
It's a different world and this government the good old USA are not always the "Good guys." - sorry, you've got your head stuck up your arse. Have a look at what's currently going on across the globe and you'll find out who the 'bad guys' are. And it ain't the US ...
You think war is a good idea? - war might not be 'good' - it's certainly not ideal - but it is necessary sometimes. ISIS need to be stopped.
Then invest your son - no. In the West, we have freedom of choice, i.e. if someone's son turns 18 and wants to join the military, there's nothing the parents can do to stop them.