Hear me out, i grew up dancing like this casually in parties. Changing partners is not insulting. You dance with someone, then you dance with someone else. You dance with your cousin, your uncle, and your brother. Dancing is not exclusive to romantic couples and dancing with someone does not mean you are in an exclusive relationship. So, they're probably friends, friend 1 didn't want to dance , then you ask friend 2 . Nothing mean or evil here