Why are us biracial women labeled as "Stuck Up"?

Okay, I am a proud ,beautiful and biracial woman who is very proud of who I am! Now I see that the "Light skinned/Black Skinned" topic has been something that has been around, probably since slavery began. I have a black husband who has opened my eyes to some things as to why I might get weird looks or stares from black women in the store. Now since reading things , I have seen that black women have basically labeled us Mixed girls as being "Stuck up" and I don't understand why. I have never came off as thinking I am better than anyone. I have always just been myself. I have A LOT of biracial friends and they have told me they have dealt with these issues too. When they go to the clubs/bars black women try picking fights with them, accuse them of trying to steal their men. This has even happened to me, I will go with my boyfriend or out with my girls and dance and the black women will come up and start trying to out dance us , or get the guys attention. I have even dealt with this from my own Sister. My dad got with my mom and had me, my mom is white and he is black , my dad left my sisters mom for my mom. My sis is all black, but the thing is we never grew up together.When she met me , I tried to make up for lost time and be a cool person to her and SHE wont even talk to me half the time. She is rude to me and calls me stuck up and all. I don't see how it is fair that black women complain about how they are labeled as ghetto,ugly and loud by the media and society for their skin and culture, but yet everywhere I look they label and stereo type mixed women , just cause they "THINK" we think we are the S***. It is is even to the point where, I get crap because I don't label myself as black. I was raised around both sides and genetically I am 50/50. My father is black and my mom white therefore I am mixed. I am not calling myself black because of some old *** rule that went out with slavery. Personally I can't help society, to me I love being biracial I get the best of both worlds and I am happy! I do feel I am beautiful due to my mixed genes, but that is the greatness of being both! That's not being stuck up, that's being confident! Why should I be held responsible for some black women's self esteem issues!