Is it really possible that you're not seeing the problem with this argument? It's so hard to believe you're just not being wilfully disingenuous. Because this is just so trivially dumb.
Seeing nudity in a setting where nudity is permitted isn't the issue. The issue is that all nudity is not the same. Being a woman and being surrounded by other naked women is completely different from being a woman and being surrounded by naked men. It's just brain-dead obvious to realise this.
Women aren't objecting to seeing other naked women, they've done that for centuries. They're objecting to changes to the law, that would remove the ability to effectively give them privacy from men. Under self ID laws, what exactly prevents me from walking into a women's changing room?? This is the problem. The "incredibly low instances of sexual assault" (just what is an acceptable amount of sexual assault for you Jared?) is a result of the fact that we make significant efforts in society to keep women and men separate in certain circumstances. As soon as we erode the ability to make this distinctions the amount sexual assault inevitably goes up.
The issue isn't simply the sight of a penis (although if it were that would be fair enough), it's the presence of a man in a space where women get naked or are trying to escape abuse from men. It's the fact that (and I can't believe you don't get this), women's bodies are sexualised in ways that men's aren't, and some men are sexually predatory in ways that women aren't. It's the increased potential for rapists to attack women when they're vulnerable. Or hell, even to leer at them while they're changing. This will inevitably drive some women out of spaces that were built for them.
I have no idea what point you think you're making about nipples. I actually agree with you though. Yes, women should have exactly the same rights as men to go topless if they choose. But even if they did legally speaking, there are social and safety consequences that mean women would never take advantage of those laws to the same extent as men. Are you really so blind that you don't see this? Do you have any women in your life? Have you ever tried to consider how women's lives differ from men's?
I'm not going any "way". It's not up to me (or you) to force women into a new social paradigm. So I'm listening to all women, women who are comfortable and women who aren't, and saying that those who aren't comfortable with changes to their rights shouldn't be forced to lose them. Because consider this; the number of women "living in fear of the penis" (again, how many women is it acceptable to make uncomfortable Jared) is greater than the number of all trans women. Women are 51% of the population. Trans women are less than 1%.
You love assuming that the number of women who object is low. The number of trans women, total, is low. Why do they not get, at the very least, an equal say? Why don't trans women have to compromise as a result of changes they've chosen to make to their bodies?
But the issue, as I've said numerous times isn't trans women. I think that the vast majority of women would be happy to accept trans women into female-only spaces if the rules to be classified as a woman couldn't be trivially taken advantage of by men. The issue, and I'm genuinely shocked to see it, is how little you give a shit about the comfort and safety of women.