I’d rather let people and friends outside my community use those words with me in a casual and inoffensive manner than dividing us by enforcing language rules against them
If that's what you want, tell them. If you came to me and asked me to use certain slurs with you in a joking way, I'd try my best to do so, but only in private and only with you. It would probably take me some time to get over my barrier to using them, but it's something I'm willing to do if a friend asks.
But that's not going to really help the next person. Slurs only have power because we give them power. The solution here isn't to normalize using particular words, the solution is to educate people about the people who those slurs target. I live in a very conservative area and have very conservative parents, and my neighbors and parents have both softened their anti-homosexual stance due to actually meeting and interacting with LGBT people. In fact, there's a trans woman at my library, and she seems to be very accepted. This works because people are exposed to real people and understand that using those slurs hurts real people.
Normalizing the terms won't do anything, bigots will just come up with new slurs. The real solution is greater exposure so people can get past the discomfort and arrive at understanding. That's what's likely missing for the boys in this picture, and it's what we desperately need if we want more acceptance.