Hookup guys friend

So the guy I've been seeing has been a friend of mine for years and his best friend and I have been friends kind of for a couple years too. Last night my best friend, the guy I've been seeing and his friend, and I hung out and the whole night the guys friend was (some what subtly) talking down on and me and the guy who I've been seeing said nothing the whole time. At the end of the night his friend straight up called me a big bitch!! And my friend and I immediately told them both to leave and they both said nothing and left. This morning the friend messages me and said he was sorry and that it came off wrong and I was just like okay bullshit. But either way I'm done having any sort of relationship with either of them. My question is how could the guy I've been seeing just let that happen hisj friend was so rude to me and he was so passive saying nothing.? They also kept talking about all the girls they get right in front of me and I was like are we trying to piss me off and hurt me??