I mean, just because someone kills you didn't make them instantly better than you though. Especially if their target priority is bad and you weren't even who they should have been going after so it's costly for their team.
Nah it just means he's dealt with more Genjis and knows how to fight against them in mirror matches. Honestly, if he can kill you every time, but you happen to wipe his team across the floor, then you're obviously the better Genji. That or your team has his specific counters. Lmao.