It's a toxic debate not because its difficult but because not being in favour unleashes a tsunami of hate and people have lost their jobs. I think of it as a series of questions to work through:
Are you OK with men who claim to be women being in women's single sex spaces - starting with public toilets and going up to women's domestic violence refuges, secure mental health hospitals and prisons?
If not, why not?
Do you draw the line at the person (men who haven't had surgery are banned) or the place (no men in a place where women are trapped)?
Why are you so concerned with the man who claims to be a woman? Why aren't you concerned about the many women that person could upset, discomfort or terrify?
What if the woman exposed to a man who claims to be woman in a supposedly safe space is actually a girl? Is it OK if she's 12 year old? 8 years old? 6 years old?
Do you have the right to consent to a mixed-sex space on behalf of every woman?
If you open the door to some men, you open the door to ALL men.