I do agree that a sexual assault is more likely to have been committed by a man than a woman. Also, I agree that more likely to commit a sexual assault than a woman.
There is no doubt that some men decide to come out as trans after they have been sentenced to prison. These individuals commonly, but maybe not always (again, I know very little about this), are found guilty of violent (including sexual) crimes against primarily women. I think we all agree that the most part they should be in the mens and perhaps a special wing as they receive transition treatment. I believe Isla Bryson falls into this group.
Is Isla Bryson trans? Not the way I used to understand 'trans.' It is difficult for me to understand how someone can make it to adulthood without doing everything they can to begin transition. It is even more difficult for me to understand how someone can suddenly and surprisingly announce they are trans after they are committed to prison, doubly so after attacking women. But, under the systems that exist at this time, Isla Bryson is labeled and treated as trans.
Back in my day (old person sounds), sex reassignment surgery was a requirement to administratively change one's sex across the government. So even if it wasn't personally desired by some, that's what a majority of us did for recognition and a viable life. We were encouraged to blend in, disappear and stay out of trouble. Being unemployed or arrested reset the surgery permission clock. Being arrested for prostitution or violence would disintegrate medical pathways completely.
I'm sure there are some trans women who are violent. Trans is a spectrum of people identifying through every possible gender-related feeling. My hunch is most trans women who socially integrate (have jobs, friends, lovers, lives, community, etc) will be just as likely as any other woman in similar circumstance to commit a crime. Trans women who find themselves culturally challenged (poverty, drugs, gangs, violent friends and community) could have heightened likelihood to commit or be a victim of crime.
This is why I believe a case by case evaluation of each trans person is fair. Violent/nonviolent offenders are evaluated for placement all the time. I don't believe gender/sex is much different.