You don't get to determine what offends others. You don't get to determine what racial slurs are acceptable if you are not a person of color. You don't get to determine what a female defines as sexual harassment. You don't get to determine what should and should not offend somebody with a mental illness. You don't get to determine what offends others if you are unaffected or obscured from the hate or harassment.
Being offended is not a bad thing. People see females speaking out against rape culture and sexual harassment as whining and a waste of time because "boys will be boys". People see those with mental illness speaking out against appropriating mental disorders as weak and pathetic. People see those who are offended as somebody who just "can't take a joke" or as somebody who just "needs to relax". We don't want to relax. We want others to feel empathy, be able to put themselves in our shoes, and see why we are hurt and outraged.
Privilege is when you don't think an issue exists or you don't acknowledge it because it hasn't affected you. Privilege is a very strong attribute in today's society. Those who have privilege think it is okay to determine this and that for the people around them. They think the world revolves the same for everybody and that there's no reason to complain if they don't see it fit to.
We are whining and complaining because we want change. We want the world to be a kinder, safer place for everyone. We want everyone to feel unified. So yes, we are offended when you are slightly sexist or racist with your comments. We don't want these things to be continued to be normalized when they are nowhere near acceptable. You can't shut down people who are legitimately working for the better of everyone.
We are outraged with the lack of empathy within our society today. We don't want everyone to hurt, we just want everyone to be aware and educated about the struggles facing minorities in society today. We don't want you to continue your racial slurs just because a friend of color didn't speak up about it. We don't want you to continue your sexist comments just because a friend laughed it off. We are scared to speak up sometimes because we are so quick to being shot down. We don't want to relax or take joke, we want to speak up, make ourselves heard, and make a significant difference.