“Two girls were staring at us with expressions of disgust”

After a night out, I took the first metro home from Chueca with my friends, one of whom I’d been hooking up with in the club. My friends got off before we did, leaving the two of us in the carriage sitting opposite two other girls. When the metro started pulling in to my stop we kissed goodbye, and as I stood up to get off the metro I realised that the two girls were staring at us with expressions of disgust – we were two girls kissing.

I don’t understand how a heterosexual couple can be full-on making out on the metro and nobody bats an eye, but a same-sex couple kissing goodbye for 10 seconds warrants stares and looks of disgust.