I've been a musician for 14+ years. I am classically trained, I have played in orchestras, jazz bands, concert bands, marching bands, rock bands, and done some studio work which is why the meer concept of someone like Ashlee is so fucking offensive to me.
You are right, a musician is someone that makes or plays music, however, Ashlee doesn't make anything--she doesn't even sing! She is an entertainer; something vastly different than a musician. I take music very seriously--music itself is something totally unique to humans as a species and when someone is cramming cookie cutter garbage down the general publics' throat, I get really pissed off. Music is not "just entertainment" to me. It is something I supplement my income with. It is something that relaxes me, or energizes me, or incites any number of emotions from me. Saying it is "just entertainment" is the understatement of the century.
I'm not attacking you, personally, for liking Ashlee, listen to what you like, but it seems like it is pretty obvious as to why people don't like her.