Insecurity causes people to do and say many unhealthy/cruel things. I call it "putting oneself up by putting others down," and it's pervasive. I have to think that confusion over what circumcision actually does makes it worse, because the guy doesn't really know what was taken from him. So he projects all his anxiety onto the intact guy(s).
As I mentioned, I have always tried to avoid disclosing whether I'm circumcised in these conversations. To say I'm not cut to a cut guy raises the unavoidable question of which is better, and that could put him on the defensive really quick. And as we know, with few exceptions, circumcised fathers are probably the worst about circumcising their sons.
That's always been my focus: protect the boy if at all possible. I don't really care what the parents think of me, and I know I have' alienated some by speaking to them at all.
It's worth it knowing there's at least one man out there who'll wonder how he got so lucky to keep his foreskin.