Chartreuseveil
You can divide transwomen into two cohorts. Homosexual transsexuals (HSTS) and autogynephiles.
Your friend sounds like the first cohort. Attracted to men, probably transitioned quite young, fairly effeminate, likely to have had surgery, and probably passes quite well.
What we would call old school transsexuals.
The second cohort are men with AGP. Or a transvestite fetish, in old money.
They are officially included under the trans umbrella, according to Stonewalls own website.
They are generally late transitioning, after decades of secret cross dressing, attracted to women, will often have feminising surgery, but, crucially, keep their penis.
It would appear, that they are often successful in IT (almost all the husbands on that thread are), or a macho profession like the military, and have often been married and fathered children.
The compulsion takes the form of being aroused at the thought of themselves as a woman. It's a strong compulsion, often progressive and fuelled by porn.
Their dating pool is almost non-existent. They rarely date each other, for instance. Because they're not gay.
They're only attracted to women, but straight women don't cut the mustard, because straight women don't sleep with 'women'. It doesn't validate their identity, for arousal purposes.
So the only cohort left is lesbians.
It means they get to sleep with women, but have their validation as a woman provided at the same time.
Lesbians are relentlessly persecuted and targeted for sex.
See cotton ceiling.
Here is a thread about a group of powerful middle-aged men who have AGP, calling lesbians hostile and campaigning to make them available for sex.
www.mumsnet.com/Talk/womens_rights/3181703-TIM-rights-to-sex-with-lesbians
Here is another thread, about all the acronyms that can drive you crazy and a breakdown of terms, if you're not familiar with them.
www.mumsnet.com/Talk/womens_rights/3145470-Break-it-down-for-me
The more people who understand the layers to this, the better. Simply saying transwomen are men, sometimes seems to people like a knee-jerk, unnecessary reaction.
So it's useful to explain how we get to that statement, which feels unkind at first, but entirely understandable when you see quite how and why it's been arrived at.