Thats just like sterotyping, no matter how much the percent of the group, its most likely it isn't going to be everyone(most of the time not majority). Thats like when people start talking about how evil arabs are and then I'm like, hey buddy, shut your mouth I'm Lebanese! Anyway, you really can't clump everyone together, I'm sure there are nice pures out there, you just generally tend to remember the bad over the good, there is more chance of you telling your friends of an instance this person was trash talking rather then saying a situation were someone had a pleasant conversation with you.