It's a paraphillia so it's like a deeply ingrained aspect of their sexuality but it works differently to how normal sexuality works. So instead of being attracted to women (only), they are attracted to being women. There's not much they can do about it. It develops by itself without the need for port, but I have no idea whether porn would have an impact or contribute to someone without a paraphilia to having a paraphilia or paraphilia-like response. But once you start spotting them on AL they become really obvious.