I'm pretty sure if the CIA knew about his future when training him to fight the Soviets, they would have put a bullet in the back of his head and be done with it. Unfortunately, the time machine wasn't working that day so I'll cut them some slack.
I'm sure some of the French liberated in WWII went on to beat their wives, rape women, molest kids, and overall lead horrible lives. That doesn't mean D-Day was a bad idea.