Why do people get upset when someone has a preference?

So everyone thought me and this guy at work were actually dating than just hanging out. The way we act around each other made everyone think especially since he doesn't talk to anyone like trying to be friends with anyone else, but with me it's different. We will hang out all day and night, one time it was so late he decided I should just stay at his house. So when I told everyone that he's not interested in me because he prefers Hispanic women, they got upset. I mean I'm not hurt or upset about it. I enjoy his friendship.

I'm the same, I'm black and I honestly only dated white guys, yes I have had crushes on other guys that wasn't white but for some reason I end up dating or being in a relationship with a white guy

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Well one of my friends told me that the only reason she got upset because of how he gets jealous when he sees a guy talking to me or when he sees me hugging another guy. And then she always hear him how he's talking to another girl or liking someone and he will always say, " just kidding" or " I just wanted to see what you would say " so her reason she didn't care about the preference part it's just how he acts.
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Also he's mixed with Hispanic, that's why his preference is Hispanic, He also likes them older, I guess that's one thing on his list that I have which is being older than him
Why do people get upset when someone has a preference?
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