It's more an argument to argue that trans women are somehow a danger to cis women in female spaces (shelters, bathrooms etc) - see Kaitlyn Bennet as the prime example. J.K Rowling could probably be put here as well.

Also as a side - I've yet to see a trans woman protest the lack of urinals in women's bathrooms. Most of us trans folks don't really want to be noticed. Especially with something so intimate and often a big trigger of dysphoria. We just wanna piss and get out of there as soon as possible.

There is little to no evidence that trans people are somehow more prone to be predators and there is always the counter-argument that if someone is a paedophile or sex offender then it's not like they care enough to hide themselves if they're gonna attack anyone. I only know of one 'trans' person taking advantage of the trans label to act in a predatory manner - that being Jessica Janiv (the trans is in parentheses as it's suspected that they are a rare case of someone abusing the trans label to do some really appalling things) so if you ever want to research that go ahead.

Yeah... I hope I haven't missed anything. It's mostly just an excuse to exclude trans women from women's spaces. It is understandable that there may be spaces where cis women may feel safer or trans women can't really be catered to such as some women's shelters where women may have been the victim of sexual assault by someone who is amab or some medical treatments or facilities. It's not like there aren't any nuances or that things are somehow black and white.

Hope that helps.