Nate. Put yourself in her shoes.... You're at a restaurant.. Someone steals money out of your pocket... You catch them at it.. They say, "Hey! I cant get money any other way!"
Or give you some other such baloney excuse to justufy their petty theft...
You'r argument still doesn't hold water. If she doesn't want her art in e book form, thats her right as the creator of that art. Will you justify theft in the physical world (Shoplifting for example) using the same arguments?
The library is a legal institution and therefore under a different set of circumstances entirely.