I will quite happily accept that ‘bad men’ may pretend to be transmen and this may cause problems. I think it causes far fewer problems than the other way round, which is obviously that bad men may pretend to be transwomen.
The first reason it is preferable is in the instance that someone is pretending to be a transman, it can be objectively proved or disproved that this person is male. If they are male, then they shouldn’t be there. The law is on the side of women.
Whereas if transwomen are allowed in the female spaces, a man pretending to be a transwoman is objectively no different to a transwoman, and so is ‘allowed’ to be there.
This is so obvious I don’t know why politicians are confused.
But even if it isn’t, let’s consider another point of view.
20% of men are over 6 foot. Fewer than 1% of women are.
So no man over 6 foot would get away with ‘pretending to be a transman’.
So at a stroke you have reduced the bad actors by 20%. And given their size, they pose over 20% of the risk of that group.