So for the most part, what worries some people here is not the existence of trans people but that unscrupulous straight cis gendered men will use the label trans-women to invade women only spaces and assault unsuspecting women?
Interesting framing.
What worries me is very specifically self-id. It's not the existence of transgender identified people. I have no problem with transpeople. I genuinely do not care how anyone dresses or perceives themselves.
What I have a problem with is policies that allow a person to self-declare themselves transgender, with no diagnosis, no oversight, and no way at all to validate their honesty. And by having self-declared, they are granted the privilege of having their internal, subjective, unverifiable gender identity override the realities of sex.
That has many branches of impact. It results in males of any type at all being granted the RIGHT to enter female-only spaces, and it deprives women of any right to say no. It grants any male who wishes it the right to go into a women's shower and see all the naked women he wants, and they cannot say no. All they can do is leave - they can surrender their equal participation in society and voluntarily remove themselves. That's the choice - be available for viewing to any male who says a catechism... or stay home.
It results in muslim and orthodox jewish women being excluded from all bathrooms and locker rooms and showers. That's it, end of their participation in society completely. Because they cannot be in those spaces with a male present. And if any male who says so is allowed to be there... then orthodox women cannot.
It results in male-bodied prisoners being housed in shared cells with female prisoners. And given the already massively disparate types of crimes committed by men versus women, and the fact that an overwhelming number of female prisoners are repeated victims of domestic and sexual abuse, that's cruel and unusual punishment.
It results in rape victims not being able to deny a male clinician examining them. It results in disabled women not being allowed to specify a female caregiver. It results in elderly women having their intimate parts touched by males, and not having the right to say no.
It results in young girls being excluded from women's sports, because males who perceive themselves as "women" have taken their spots. It results in males who make a claim to be transgender to set records for women's sports that women will never be able to break. It results in women experiencing injuries far beyond what another women could cause.