Firstly, not DH - DP. Please. Marriage is a ridiculous, patriarchal fantasy, so please don't assume it.
"It's about being a unwilling participant in their active fantasy, being forced to participate even though you know that this stranger is getting off on your discomfort. Not be able to say no because you're trying to do your job and not get told off for losing a customer, or worse, be accused of transphobia."
No-one was being a participant in a fantasy, just the facilitator of a purchase of underwear which society has decreed to be exclusively for women.
They didn't have to see my DP in a state of undress, and there was nothing sexual about the shopping trip. Indeed, this is not a particularly sexual fetish in DPs case.
We telephoned in advance and had a very frank conversation with the department manager because we specifically didn't want anyone to be discomforted or embarrassed. Consent is everything in any situation remotely like this. Manager said, and I quote almost verbatim, that it was a 'very common request and they were happy to help'. They told us to ask for a particular staff member who was experienced in this kind of request.
I'm not sure how we could have been any more respectful. So I guess you're saying that men cannot buy 'lingerie' for themselves in person in any circumstance whatsoever.
You make an awful lot of assumptions AssasinatedBeauty, but I don't think you're particularly interested in the reality of the situation where it doesn't fit with your preconceptions.
Some of which I think are pretty ignorant, actually... I don't think you know many people who cross-dress - since you seem to have pigeon-holed it as some kind of sleazy, filthy, exploitative exercise.
In many cases it's not a remotely sexual thing.