A vulva is not a physical danger to men. Men have single sex spaces for dignity purposes, not for safety.
No it's not a danger to the men, but it's a danger to the owner of a vulva:
Absolutely agree this is a self-ID issue far more than a trans issue, in fact, it's not even a self-ID issue truth be told, it's the potentially inherited rights that self-ID would like to inherit that are the issue, but, since it's impossible to determine the difference between a genuine trans and a faux one using self-ID as a mean to gain access to a female space, then legislation has to somehow try and cater for both instances - a VERY difficult task.
So let's take just some of the multitude of scenarios:
-
A born male wanting to be a woman with no desire for surgery.
In this instance, he wants to be treated as a 'she' but cannot enter women's spaces so has to enter the men's. This is a danger to the transwoman (absolutely due to men's awful behaviour).
If this person enter's a female space, women can be exposed to a penis, and can't know if this person is 'genuine' or not.
-
A born male wanted to be a woman and has undergone surgery.
In this instance, many women have much more faith that the trans is genuine (due to surgery), but argue that the person is still biologically male. There 'seems' to be more acceptance of this person in women's spaces, but it's by no means universally agreed.
-
A born female wanting to be a man and has not undergone surgery.
If this person wants to be treated as a man and wishes to join the men's areas, they're in real trouble. Once again, this is absolutely down to men's behaviour, but as things stand today, a naked female with breasts and vulva in a men's area is a problem.
-
A born female wanting to be a man and has undergone surgery.
Unless the surgery is incredibly convincing, they are probably in for a rough ride in a men's area, again down to men's awful behaviour.
So there's only really 1 scenario where acceptance might happen, and even that's not universally agreed. The other 3 scenarios present a real problem for trans.
Again, I use the word 'trans' generically to include those with a true desire to change their gender, and those who might self-ID either on a whim, or for ulterior motives. Sadly, it's not possible to differentiate them unless they've had surgery, and even then there are cases of those who have had surgery who've regretted it, or turned from man, to woman (via surgery) then turned lesbian, which makes for a very complex deciphering of sexual motivation.
For me, Self-ID per se is not the problem, but gaining rights 'just because' someone Self-ID's is. Also, the safety issue in women's areas is obviously a huge issue, but it's not the sole motivation for protecting women's rights. It should be a right regardless of safety, as it is for men.