Suggestionsplease
Here is part of the answer to your questions about AGP as a private fetish: like all fetishes, it involves attaching sexual meaning to objects, properties, processes, or body-parts that do not, in themselves, have a sexual function. There are, for example, e.g. Qing-era Chinese woodcut images that are uncoloured, except that the women’s feet have been picked out in red.
So far, you may think: well, we have to accommodate such people. They are apparently gender-non-conforming, mixing it up, breaking down the boxes, which is what feminists have wanted and have been doing themselves for some time. "Old-fashioned" transexuals were terribly gender-conforming—only it was the opposite gender they wanted to perform, and in every aspect of their lives. An AGP man isn’t like this. He’s a pervert with rose-tinted spectacles about women and a rose-coloured basque.
He looks on female underwear as a sexual prop for himself. He likes to carry it to work with him, to bars, to the game, to PTA meetings maybe; its being secret is part of the thrill, I guess. But if he’s married, maybe (probably) his wife knows about it. Maybe she’s been persuaded or coerced or bullied into “sharing” this secret life. The husband wants to wear this underwear in bed with his wife. Then he wants to play “the female rôle” (which means: being penetrated) while his wife plays “the male rôle”—she has to pretend to be a dominatrix so she can penetrate her husband. He starts wearing female clothing in his leisure hours. He ventures out sometimes in it. Gradually he begins to wear it all the time. He “comes out” as TG.
Now not every male female-underwear wearer goes down this well-trodden path. Some stay at the first stage for decades. What’s the harm in that, you ask?
First, because men who dress like that, also feel a certain way about women. They covet for themselves a very restricted vision of things that they think women have or do and they don’t, not yet: wearing soft fabrics, silk and lace; being able to adorn their persons and be complemented for it; being looked at and admired; being the object of desire. In their minds, they are a woman… but only because of the sexual gratification they receive from being treated “as a woman”, and from women treating them and accepting them as women. Whether we’re talking about secret underwear or surgery, the whole AGP thing is born of a man’s sexual desire to be seen as and be treated, not as a woman, but as he imagines women are and are treated.
Somehow he doesn’t associate being a woman with being paid less than men, being exploited or sex-trafficked, being intimidated, controlled, abused, beaten, raped, or murdered by a partner or ex-partner. He does not demand to be paid less in solidarity with "other women”. He does not start demanding to be given the lion’s share of housework and child-care. He doesn’t start worrying about heavy periods or the effects of the Pill, or about developing polycystic syndrome or breast cancer, or about how menopause will hit them. He doesn’t instinctively avoid dark alleys, dark corners, or anywhere alone with a strange man. (BTW, the murder rate for TG people is lower than it is for the rest of the population.) His is a narrow, sexualized imagining of what being a women involves. For him the “female rôle” is an exciting part in a sexual drama he wants to play again and again and again.
Second, if a man is wearing women's clothing, but otherwise does not perform the female rôle—that is, does not behave as women are conditioned socially to behave—then he will stand out like a sore thumb. There is no getting round this, as yet. There will unavoidably be a cognitive disconnect for those who engage with him, men and women alike. A very tall person in high heels and a short skirt and bright red lippie, who likes talking over people in meetings, is always competitive, can be a bully, is known to drive a powerful car fast and hard, tweets about violent assaults on women’s bodies, conspires with other men to drown women’s criticism of them and their language—all of this behaviour will remain “masculine”. (This is not to say that women cannot be domineering and loud, only that they are conventionally associated with the masculine gender, whereas heels and so on are not.)
So why does this person change their dress, their hair, etc., but not their personality? Why is it just this one aspect of themselves that they have opted to change? What has happened to the rest of "femininity"? Lots of gay men are feminine in various ways—they often like cooking, interior design, clothes, and talking about people and relationships, and often make excellent friends for girls and women. But they wear men's clothes, have (and like) men's bodies, and are definitely men. These men are… what?
This sort of lop-sided "femininity"—high heels and a domineering, look-at-me, violence-loving personality—will be familiar, at any rate to Mumsnetters, from the very masculine abuse and threats of violence, including rape, hurled at “TERFs” and especially at lesbians, who are, of course, very sensitive to these threats, since PWPs have been threatening to "set them straight" with a good dose of cock since time immemorial.
Feminism taught us that “the personal is political”. In this case, that men’s personal choices come from a perverse, incomplete, distorted understanding of women and what it is like to be a woman. He has cut out all of the unwelcome political consequences of that condition and left only a conventional sexual rôle. And the sexual fantasy they construct for themselves is always also for the women around them. They are part of the drama. They can provide validation, if the person transitions to wearing female dress. At the very least, they are also wearing female underwear. How exciting is that! How wonderful and erotic! How could women ever complain about bullying in the workplace or equal pay and conditions or paid maternity leave when they get to go that mAg!cål WºnDerfuŁ place that is Victoria’s Secret and try on padded bras and silk thongs with other women in cubicles around them and no one bats an eyelid! It is so unfair!!
And this is not to talk about which bathroom he will use and how womem will feel about having to accommodate his fantasy. They may not have transitioned physically at all. That person in a short skirt and heels may have a penis and testicles under there. And as we women don't know either way, then our penis-radar will be pinging away like mad. Unless we know better, that person will be perceived by women as a potential threat. We will avoid being alone with this person, apart from others, either inside or outside, unless we know him well and/or someone they know well can vouch for him. We will not readily give him our phone number or address. We will not engage in intimate conversation with him. And so on.
Yet this man's feminine dress is a message to others that he wants to join female conversation and to enter female spaces. So which loo do they use? Do women always have to go to the restroom in couples? This person's behaviour has, in effect, forced these women to accommodate his desire to wear women's clothing while not changing in any other way.