You're going through an obvious case of selective perception.
Romance day is just another name for Valentines. MrDots has changed every real world reference to his own; i.e. country names, band names, celebrity names, pop culture names, etc.
You're as subtle as a jackhammer and I realize you're not happy seeing non-European looking characters in your porn games, but it's not like MrDots isn't inclusive. From the general look of where the game is set, it's clearly a Mediterranean country. Ask any Spaniard, Italian, Greek, etc. and they'll tell you that there are definitely people who look like the MC's old band members who are native in that area.
Xianne is one character; not "everyone" like you said. And it's clear it's a setup to get a foursome scene with Melody, Sophia, and Xianne (referencing the walkthrough), as all 3 of them are now OK with getting it down with other women.