It's an ability which 'fires your weapon'! Disarm doesn't actually say that it prevents the target from firing their weapon, but that's about what I'd expect it to do. Kinetic Carbine is prevented from being fired by Disarm, and it's also an Ability.
This is just a specific exception carved out for Bullet Dance. I think it's fine as a thing to exist, but I also think it's not surprising that it's getting bug reported.