Lennon was abandoned by his mother.
He was raised by a very abusive aunt who brow-beated him. (She continued to treated him like a failure even after his Beatles success.)
Lennon spent his life trying to prove he wasn't a failure to his aunt and to himself. It messed him up.
The drugs exacerbated the problems.
As for the song "Revolution," as others have pointed out he regretted parts of it. And in the "slow version" he says "you can count me out -- in..."
But regardless of his inner conflicts, his public persona at the time was unmistakably against the Vietnam War.
No doubt. The point of my post - which wasn't specifically directed to you or anyone else - is that it's a mistake to try to pidgeon hole him.