This

I think compared to the US men who transition in Iran are less likely to be autogynephilic and are more likely to be feminine homosexual men.

and this

I’m also uncertain if researchers in Iran tend to be unbiased toward homosexuals as homosexuals aren’t accepted in Iran

are good points to keep in mind. To be clear, though, I don't mean to suggest that AGP transwomen have a monopoly on personality disorders; while they may or may not be driving the trend, I think it is worth considering in the context of HSTS people as well, because transgender ideology can be cultlike and narcissistic and draw people who are high in those traits. I think the rate is largely so high because personality disorders are far more common in clinical populations, period; but cultural context and homophobia-based discrimination are important to keep in mind.