On another news article about similar, there were comments that it was ok because women sexually assault each other as well.
The other argument is that male guards sometimes assault female prisoners, therefore we are hypocrites for objecting to male prisoners in women's prisons. This is particularly vile because it ignores the actual problem - putting violent male offenders in with women prisoners - in favour of an ad hominem attack on those of us who are campaigning to support the most vulnerable women in society.
The logic seems to be that if male guards - who, I imagine, are generally vetted for previous convictions - are a danger to women, then we might as well stick in some actual rapists because it's all the same.