If Sam got offended every time Gene said something harsh, it would be a constant state. No one wanted to live like that. Sam learned a long time ago to let most everything Gene said roll off his back, no harm no foul. Sam assessed that most of the time, gene didn't even mean to be offensive, that's just how he was.
Sam opted to stay quiet, and drink his beer. His glass nearly empty, he signaled to the bartender he wanted a refill. At least drinking felt normal, when nothing else did.