I suggest that "vagina" is US terminology for pudenda in its most general aspect. The imprecision can be excused given that the population of our once-great nation is not known for its proficiency in matters of either sex education or geography.

Can we agree that these apps should be renamed antisocial media?

I'm not sure what planet you live on but the one where I live, the general term for female genitalia is a "vagina". I've never heard someone say, "kiss my vulva".