Because she's a trans woman, will likely be wearing trad 'female' clothing and answers to that name.
Because she's clearly vulnerable and disrespecting her is going to add to her distress.
Have you stopped to think about the damage this may do to her mental health? Being judgemental about her appearance is likely to cause her a lot of pain.
She has done absolutely nothing to deserve all this malicious attention.
Spare me the fake concern, this is point-and-laugh bullying disguised as caring. She doesn't deserve this and neither do her family. No wonder so many trans people are driven to suicide and targeted for violence.