My girlfriend wants to break up since I’m not fond of her black sister

I am a 25 year old male and my girlfriend is a 22 year old female. She has a black sister who is 27. I am a black man. <br><br>My girlfriend’s sister is very annoying and always gives me negative comments. For example she once said “You are too nice, people take advantage of you”, “You are easy going but that’s not a good thing”, “You will never find someone who loves you since you are too easy going.” Her comments upset me since I feel that I am a bit selective in the things I do. <br><br>Yesterday I lost my temper and told her off. I told her that her negative comments are annoying and I wished she wouldn’t say them. <br><br>Now my girlfriend said she wants to break up with me since I showed her sister no respect. I feel that it is ridiculous. I am entitled to my feelings and I don’t think it’s right that her sister puts me down and I stood up for myself. <br><br>Am I in the wrong? Should I have just kept quiet?