This resulted in many cases later of developers contacting me to ask me why some bizarre bit of code was in the app in the first place. I always referred them to my manager with an NMP (Not My Problem any more).

I hope this isn't a real story. It would have taken you just as long to refer them to the commits with your comments still in, and run a git blame to show your manager took them out. Instead you just make yourself look unhelpful and incompetent.