Welcome to the real world where girls kiss each other all the time, it doesn't have to be of a sexual nature and even if it is when done during a 'dare' game, they have no hang ups about it and they don't do it because they are lesbian.
This game is about the MC, who is male, so everything that happens in the game revolves around him, I don't think I saw any scenes where he isn't present, but if girls kissing turns you off then I don't think adult games are for you, as most of the ones I've seen have girls kissing at some stage.