As a photographer I don't shoot porn but I do shoot glamour, topless and nude etc so I can to a degree understand the mentality. Once they have broken the ice ice it's not actually that daunting. It's a case of the old "if you've got it, flaunt it" mentality. Many are quite proud of the kudos that comes with it.
On the other side of the coin, there are those outside the industry who can be quite judgemental about it. From my experience, a lot of that comes from their own insecurities or jealousy about the attention the models get.
Within the industry there is a lot of frustration with stereotyping. Models get called slags, sluts etc and photographers get called pervs!

The problem being that many outside the industry relate nudity with promiscuity. Models often get tarred with being thick and easy. The truth is that many are intelligent with degrees and high moral standards.
I have been approched to shoot porn but I have declined. I have nothing against those who do but personally, I would rather keep some things special for my own bedroom. I'm quite happy to concentrate on genre's that are more tasteful and artistic and setting my limits to erotic art.