There are people who exist that just have "something" about them. Be it general charisma, an aura of charm, whatever. I think Katra is one of those. She's "useless" but she's charming, unassuming, generally kind and caring, never judgmental, and also apparently very good at listening and just being there for someone when they need it. I can understand why others would be drawn to her, and the fact that she's also completely blind to her own situation, oblivious of the conflict she's been brewing, makes all the drama make sense to me, ESPECIALLY when she's been around Kidaha and polyamory for so long that hooking up with more than one person is a natural thing for her to do.