"Looking for girls who want boys
Who like boys to be girls
Who do boys like they're girls
Who do girls like they're boys
Always should be someone you really love" Blur
"You don't have to understand, just don't be an asshole about it" is it.
My dad (70-year-old college prof) was talking about trans students and said "It doesn't make sense to me, but you know, my dad didn't understand long hair on men when I was a kid, either. I just try to be nice." Works for me.