Bumped into a Hiring Manager who had rejected me

Interviewed at Adobe and Hiring Manager took me out for lunch. The loop went great except an interview where they had a couple of interns who grilled me on syntactical errors and wanted runnable code on whiteboard. I bombed that interview because I was like WTF in my head. Not because it was interns, but because they didn’t really know stuff. I was pissed. The day after getting a reject email I am at a grocery store and bump into the hiring manager. I say “Hi” and asked him “what happened ?”. He said “We didn’t find you as a right fit.” and he walked by. I have since then replayed the scene umpteen times in my head seeing myself burning him. I feel I missed the chance to at least give him the right feedback on how he should train his interns how to interview. How would have you roasted him ?