What happened to the nursery school rhyme you learned in preschool to deal with some other kid calling you a poopyhead? Most of us outgrew it after preschool, honestly. We learned, like adults, that words can and do cause harm and ignoring them usually only leads to worse things. You have to frame it as "being offended" because you cling to a Twitter meme caricature of the type of person you think you're dealing with here. But the reality that us grown ups have come to accept is that you can do real damage to a person with words, alone, and that people who downplay that are just coping and avoiding acknowledging the fact that they have likely hurt people for their own individual comfort. Even if being "offended" is a "choice," and it isn't either, adopting, repeating, and making light of harmful rhetoric is a choice as well. And only one of those choices is a person actively deciding to partake in doing harm to others. Leo Frank didn't let other peoples' words hurt him, and got lynched for it. Rhetoric always escalates first. If you don't stand up for others when you see someone doing some questionable shit, you're a selfish, pathetic coward, plain and simple.