It seems like the issue is that the Womens and Open titles aren’t directly equivalent in terms of their requirements, then? Since it would be unfair to give a higher title when the person hasn’t earned it, and there’s no title with the same requirements, then the nearest equivalent title would seem the only option.
I also suspect that the likelihood of someone being trans and having an extremely high title is quite low, and for the majority of trans chess players, the transfer would be between lower ranked titles, and when they are not as well-known, which means it would be both more viable and more important for their privacy to be respected. That said, I do agree with you that it should be down to the trans person to choose what they want to happen with the titles they’ve earned. I just thought it was worth pointing out that transferring trans men’s Womens titles to the nearest equivalent Open title is a good policy, even if it was implemented unintentionally.