Yeah, what were you thinking Carmine? Everyone is the best player to ever play league of legends in that community. I mean, you should feel honored just to have them on your team. They obviously could have won a 3v5 because you and morgana were disposable. [/sarcasm]
Yeah I donno the LoL community is, not surprisingly, a lot like the DotA community. It's full of elitists. Your example is a bit more relaxed than what others including myself (and I'm sure you have) experienced. For this reason I exclusively play with eGO people.
However, the opposing team will still occasionally become hostile when they lose. Even without provocation. The funniest is when you win and they call you a noob. Honestly, I'd rather be a noob than lose to one.