You can argue until you're blue in the face that what this guy did is illegal, except that there are enough vaguely-written Federal laws that lots of innocuous / morally sound practices
can classified as illegal.
You can run around in circles and howl about the troops, and then you can bite me. If you strap on your country's uniform, pick up a gun, and step onto a transport, guess what -- it's gonna be dangerous, you might die, and that's just part of your job. I don't want our troops dead, I'd prefer they all came home safe and mentally sound, but I can hardly take it personally when someone else beats them to the punch.
If you can't accept that, don't sign up, not even in peacetime.
Treason? Treason against what, an abstract concept embodied by a metric ****ton of selfish pricks that don't give a **** about you personally, who work constantly to increase their authority over your life and erode your rights, who take your money and use it to buy votes, campaign dollars, and favors from powerful people?
Really? I'm supposed to get upset because someone made THAT bunch of assholes angry? Or because being a soldier continues to be a risky, thankless job?
When the feebs are less interested in collecting scalps or taking bribes and more interested in actually being public servants, I'll reconsider my position.