This would make more sense. It's a very different problem if trans people "can't get passports anymore" vs being able to get their preferred gender on a passport.
Of course, the use of the term 'preferred gender' is the issue here (I don't mean with your reply), since to trans people such as myself, it's literally who we are.
Imagine someone that has transitioned and passes as the sex they identify as, now only having the option of getting a passport as the sex they were assigned as birth.
Practically, for many, that simply isn't an option.
Someone asked more why it was not an option but deleted their comment before they could answer, so here is my reply:
There is a issue with fear and using the passport.
Border agents have pretty much complete discretion and control at all borders in all countries against non-citizens. Any border agent can deny entry for any reason, or subject someone to extra searches, maybe strip searches, without any consequence or any recourse from the traveler.
Given the amount of transphobic people, this is an issue. Imagine if gay people had to get passports in the 90s or 80s that marked their orientation?
The second issue is a huge issue as well, that could easily lead to an increase in suicides.
As I see it, it is an option but there is a cost. You're making an absolute statement when it seems like it's that you view the practical cost of choosing the option as too high. Which is fair but you're refusing to explain the costs. Is it physical harm? Is it emotional harm? Is it future inconvenience? Is it fear of future physical harm? Etc. Etc.
The risk of physical harm and harassment goes up significantly, imagine a transwoman trying to travel anywhere with a passport that indicates male, they can be detained, searched for any reason. That's just one obvious example. There are plenty of other instances where physical harm might increase, and yes emotional harm is a big issue as well, not least because it's a clear attack on dignity.