I think that people misunderstand what racism, sexism and privilege fundamentally are. Fundamentally racism etc. is an institutional issue. The focus is not on individuals but on the way society creates and enables racism etc. Saying that racists/sexists/homophobes are bad people is stupid and naive. It misunderstands what the issue is. Racism, sexism, heterosexism, transphobia etc. are part of the system of patriarchy. Patriarchy is basically those with power having privilege over those without power. Patriarchy includes race, class, gender, sexuality, religion and other categorizations. It varies from society to society changing over location, subculture and time. The culture and society itself is racist in that it gives privilege and reinforces privilege in populations (think the way news is framed and media, if you want examples ask me for some).
This influences the actions of individuals. Some people are assholes and so use phrases like ni**er and fa**ot and whore to cause fear in others. The reason they can cause fear is because of the privilege they have in the society. If men are cat calling a woman, in general, it is not because they want to cause fear but they have been taught by society that there is nothing wrong with it and that it is harmless. If a woman feels threatened by this it is because she recognizes her lack of privilege and her vulnerability in the situation. If a person makes a joke about black people liking watermelon they are not doing so because they are racist, though they can be doing it to be an asshole, they are doing so because society is set up in a way that makes those jokes permissible. If a black person hears these jokes and feels awkward it is because they realize that if they speak up that it makes them uncomfortable they will be told to be quiet, or to loosen up. They realize their own lack of power in the situation.
The issue here is that people are part of society and influenced by society at large. When people say sexist and racist things meaning no harm they can still be good people, they can simply be ignorant. If someone is saying racist and sexist things on purpose, they are being an asshole not a racist. These are two separate things. This is a very nuanced issue and I hope that people can incorporate these differences into their speech and stop being confused about this issue.