I fell down the rabbit hole in 2009, when I dated a guy with agp for just short of a year, starting when I was 16, and he was 18.
I didn't learn the term agp, until I read about it here much later, but he fit the description to a T. He'd spend the majority of his spare time gaming, was an IT buff, and wearing womens lingerie or clothes, would turn him on to the point he'd ejaculate, without even touching himself. I eventually discovered he had several fetishes, found humiliation a turn on (but only when dressed as a woman) etc.
At first he said he was a cross dresser (didn't bother me at all, I'd been a goth and my music idols were guys like David Bowie and Brian Molko). I was already highly gender critical.
When he wore womens lingerie or clothes, it brought out another side to his personality, called -female name-, and he asked could I call him by that name when we were in bed. We tried pegging (which I didn't mind either). But, the more I saw what his idea of female was, the more it turned me off. He was overly masculine and aggressive most of the time, then when he got the chance to dress up, (always in an overly glamourous, sexulused way), he'd act coy and simper, head to one side, baby voice, etc, but during the act could be very coercive and sometimes abusive. I never saw any actual feminine behaviour from him. When he declared he was a woman trapped in a mans body, I almost peaked, within a day or two, and tried to end the relationship. It took me a long time to get my feelings about it all straight, but the only sane conclussion l could come to, was that my ex had been a misogynistic, abusive, pervert, and that I couldn't let myself feel sorry for him, or guilty. He struggled to let go of the relationship, and eventually got nasty. I soon realised this was because his relationship with me, my support and the lies he'd hoped I'd tell for him, would make him seem more legit to everyone. He'd already admitted to lying to his Dr's about various things.
I found threads about similar men, and transwidows, and was shocked to see I hadn't been the only one to meet one of these guys, and felt so angry on behalf of the women these men had manipulated and lied to. Then the situation got more and more out of hand, the until I read about the new brownie policy and truly peaked. Anyone who claims there aren't men out there, who would do literally anything to get get themselves off, including impersonating a female, is naive or lying.