If someone likes her music because they actually enjoy listening to the music, then okay.
What irritates me is when (usually in person, I actually haven't seen anyone pull this here), after I politely state that her music isn't for me when asked about it, some people just don't accept that as an answer. My favorite tactic has to be 'But she's actually talented! She plays the piano!'. It doesn't change the fact that; a) That isn't reflected at all in what she has commercially released. b) I still don't enjoy anything she has released.
I will give her credit for one thing; she knows exactly what she's doing. I just really don't like what that is.
Edit: I'm not against all pop music. I'm a pretty big Michael Jackson fan.
Gaga's music, to me, just seems so empty and calculated.