It is a grotesque misapprehension which sees in art no more than a craft comprehensible perfectly only to the craftsman: art is a manifestation of emotion, and emotion speaks a language that all may understand.
She honestly didn't think what she was doing was any different than donating money for a library or athletic field. That's the crux of why she pleaded not guilty.
" You conjecture is totally wrong, I assure you." said Darcy, " My mind was more agreeably engaged. I have been meditating on the very great pleasure which a pair of fine eyes in the face of a pretty woman can bestow . "