Hanzo probably looks vaguely uncomfortable/guilty every time Genji hangs around him and makes brotherly gestures now bc he’s still riding the “oh my god i tried to kill my baby brother i cannot be forgiven for that” train that returned with a vengeance when Genji reappeared.
Hanzo has a lot of stuff to work through. Genji’s had 10(?) years to look back on the event and what happened and who he is now and come to terms with it and forgive. Hanzo was basically hit with a feels truck + paradigm shift when Genji reappeared into his life so he’s pro ba b ly reliving the consequences of what he did pretty hard all over again.
Anyways, I’m p sure Genji just aggressively wants his big brother to be his big brother again