Girls gone wild, y'all

A few days ago, one of my bestfriends was hanging out with this guy I'm seeing, and they were making jokes and stuff, which is totally normal, there were two girls watching them, one of them is his ex-girlfriend, and the other one is one of his bestfriends. Oh, and they don't know we're dating, only my friend knew, anyway, when my boyfriend walks away, one of these girls come up to my firend and says:

  -IT*: Look, are you in love with (the guy's name)?

  -AR: No, you can tell her (his ex-girlfriend) I'm not...

  -IT: What?!

  -AR: Never mind...

  -IT: Oh, because if you are, you're gonna regret it...

*IT is his friend, AR is my friend

I mean, who the fuck do they think they are?!? For the love of  whatever. Even if she was in love with him, what would they had to with it? Really, what's happening to girls of this century, are they going crazy?!? (I actually need the answer...)