Here's another transgender person (an attorney in Illinois) complaining about an "everyone must use their legal name" policy - namely the rule that all attorneys identify themselves by their legal name when practicing in court.
In her case, there are two things she mentioned that I'd like to rebut:
1. She mentioned the time it takes from filing to the granting of the name change, and how she started living as a woman before she started the name change process. If she knew that she'd be required to use her legal (in her case her old male) name on official documents/proceedings, she should've planned ahead to do the name change around the time she started living as a female in her professional life. (I'd have a little more sympathy if she had financial or other barriers to legally changing her name, or if she was still indecisive on what she wanted her name to be, but neither appears to apply here - considering she's an attorney herself and she had been using her chosen name informally.)
2. She also brought up the point that names can be changed at marriage via a marriage license without a court order, and she felt that she should likewise be able to change it with just a therapist's or a doctor's note. There's an important difference there though - a marriage license is a legal document that is legally recognized as a means to change one's name, while a mere note from a medical professional is not.
(Since I do respect her decision to transition from male to female I use female pronouns, but not her decision to live as a woman without at least beginning the legal process to change to her chosen female name at around the same time if she knew she'd have issues using it officially in her profession without making the name legal. As with previous posts in this thread it'd be different if non-transgender people had the option to use a different name from their legal one, but this is a policy that applies to everyone.)