There's a reason they don't want to have an intelligent discussion.
It's because all the reasons why trans women should be in women's spaces ultimately boil down to one: because they want to be.
Humans can't change sex, and gender isn't actually real. Nobody who believes in gender can explain what it actually is without resorting to stereotypes which the majority of people don't conform to anyway. Nobody who believes in gender identity can explain what it is other than simply having a personality, or what their gender identity has to do with anyone else.
This whole ideology is a form of extreme individualism. I want to be a woman and I believe I have the right to force the whole of the rest of society to deny the evidence of their own eyes and pretend that I am a woman, regardless of what impact that has on their ability to feel safe and comfortable in changing rooms, access rape crisis services or compete fairly in sports.
As soon as you start trying to discuss it rationally, it becomes clear that gender ideology is indefensible and unworkable at a societal level. You simply cannot give these rights to trans people without others suffering as a consequence.
We could have that intelligent discussion and eventually land on a compromise where we address trans women as "she", we don't abuse or harass people for wearing gender non conforming clothing, we don't discriminate against people in employment or other areas of public life for presenting in a certain way, and where, over time, we create additional third spaces for trans people so they can use the toilet and get changed safely and with dignity, without encroaching on women's spaces and compromising women's ability to do exactly the same.
But that's not a compromise we are ever going to reach because it's not what they want. A women's toilet without any women in it is just a toilet. A women's swimming competition without any women in it is, well, a men's swimming competition.
Ultimately, it is an ideology which just doesn't make a damn bit of sense, and politicians on the left and centre probably should have thought about this before hitching themselves so publicly to the trans rights bandwagon.
I mean no disrespect to trans people, or rather, people with gender dysphoria, when I say this. And ultimately I think they are starting to lose public support and the zealotry of the trans activists will ultimately cause innocent trans people untold harm.
But this is the reason why they don't want to have an intelligent discussion. It's why reasoned debate must be prevented at all costs. It's why women must not be allowed to speak.