I actually think that it is not sick but stupid. When I am aroused I like it a lot, but when I finish I feel like some idiot and lose all interest for an hour or so.

I like practically all porn and many fetishes focusing on some single thing makes no sense because you will be bored to death. how long can you enjoy same stuff? So yes I sometimes don't mint to look at pretty softcore stuff which would not be even considered porn and it may be no less arousing that most heavy content as for example women with big breasts are way sexier when clothed than naked.

I guess there is a reason to be ashamed but not any more than liking sex in general because this is just a plain stupid thing if you think rationally. But on the other hand, shame is what makes it sexy.
I guess the reason why you don't like plain porn is probably you are not ashamed of that :) there must be some contradictory feelings where you desire something but at the same time know that it is wrong.