I honestly can't get too worked up about whether a rapist believes they are male or female. Clearly I'm in the minority but to me the term #notourcrimes applies because I'm one of the people who has never committed rape or sexual assault, not because I'm female.
There was a thread a few weeks ago about the Northwich dog abuser. I said then what I'll say now, I genuinely don't care whether someone like that is locked up in a male prison or a female one, the important thing is that they are taken away from society. Any future crimes they commit whilst in prison are not OK, but at least they will be committed on fellow prisoners rather than the general public. Prisons are not nice places, they're not meant to be nice places, the fear of getting locked up with a transgender rapist for 23 hours a day serves as a good deterrent not to be sent to prison in the first place. I don't want them to abuse a female prisoner, I don't want them to abuse anyone - but if they do, better their victim be a prisoner than a normal person.
To me it doesn't matter whether crime statistics are skewed by so-called "female" rapists. What matters is that rapes aren't committed, and if they do that the offender is locked up. Suggesting it is harmful that a transgender rapist has their crime recorded as a female one implies that the victim is less of a victim because their attacker was "only" a woman. I'd suggest many rape victims are traumatised by the crime itself, which prison their attacker ends up in and which list the crime is recorded on is only a minor concern.
Society has evolved and now believes that someone can become a member of the gender they were not born as. Whether you think that's right or wrong, that's where we are. There were similar arguments when rights for homosexuals were being promoted decades ago - they were identified and treated differently in prison because they were deemed at greater risk of attacking others. If we believe a person has the right to choose their sexuality, now their gender, we must allow them that right without limitation. We can't say "well you can live as a woman except when it comes to playing sport or going to prison" - either a man can transition to become a woman, or they can't.