I wouldn't go straight to the notion that it is an attraction issue, more than it is one of porn being habit and comfort based.
At least personally, I consider sex with my partner totally separately from porn. One revolves around intimacy, the other is more of a psychological comfort zone that helps me de-stress.
I suppose what I'm saying is that the mechanical aspect of masturbation is more of mood/stress tool than it is an indicator of attraction.
Not sure if that makes sense.