Automatically pairing people by gender is pretty weird IMO. As a trans woman I have to find my own roommate or find an organizer to intervene and explain my life story to them.
The choice works for 99% of people, and it’s always very clearly stated. If you have any problem with the default choice, I am sure the organizers will do their best to accommodate your request.
The same holds for special dietary requests, special assistance, people arriving late or leaving earlier, people traveling with partners, with children, etc...
I don’t want to be rude, but please just realize that usually the defaults try to accommodate as many persons as possible, and then there’s always the possibility to ask.
Do you have any better solution? I would be interesting in hearing what you think!