Mixed dances

And Miriam and the women of Israel in the wilderness.

Miriam and the women of Israel in the wilderness danced separately.

Sure. Behind a partition.

Simply put, on Tu B'Av, this was for the purpose of looking at the beauty of women (after all, this is for getting married), but in casual dancing, there is a prohibition against looking at the beauty of women (in marriages where there is a dispute as to whether it is Torah or rabbinic, and in rabbinic divorces, Beit Shmuel on the Shulchan) even before contemplating transgression.

What is the question? It is clear that if he does not contemplate the beauty of women, and does not touch them for the sake of affection, there is no prohibition, and even the great Amoraim danced with women [he put a veil on his shoulder].
And if he knows that he might touch her for the sake of affection, or look at her for the sake of pleasure, it is clear that it is forbidden, and what if that is the question? Examine yourself and decide.
As it seems to me that to do this and not fail, one must be either a supremely righteous person or a great wicked person [whose heart will be extremely attached to this, until he is not awakened to something beyond the mere act of dancing], and the fact that they practiced something does not mean that it is okay or that it can be tapped.

Your Honor. Regarding mixed dances, in my opinion there is a clear difference between the examples in the sources you cited above and the relevance of the question today. For example: My brother is secular, and when he wants to enthusiastically show me the party he attended last night, I forcefully watch the video of the many he filmed. In them it is difficult not to feel the light-headedness of the dancers, some of them (Yaan) with tsitsiyyah moving from side to side with their eyes closed with a drink in their hand and a potion on their head, while next to them stands a woman in her own world enjoying the moment in exactly the same way.
It is clear that if the public with the tsitsiyyah (Yaan) chooses to dance next to a woman, even if this is done it will be without touching and without light-headedness, etc.’
But he will not do so, from the judgment of a person who will truly fear heaven. With the understanding that it does not belong to a person who fears God, and only when we reach the steps and the clean culture that was then, we will be able to think about it, but then it will not contradict the fear of God. Today we live in a different reality in my opinion.
My brother always gets angry with me when I tell him that I do not want to see videos of him and especially with women dancing – But he does not understand that when his life story began with cigarettes in high school, ‘Not keeping the covenant’ Towards the end, ‘Cigarettes’ And trips with mixed company, and parties every day and drunkenness - in short - an immodest secular life that I doubt has no irreversible impact on the soul, and here I am, in my third decade, still fighting every day at the basic level of keeping the covenant, with the filtered device, and who has never touched a woman -
Of course he will never be able to understand me, he is immersed in a ’swamp’ and will turn the world upside down to justify his situation because in my opinion he does not understand how serious the situation is. Dealing with this question is legitimate but in a forum of God-fearing, clean-minded, and not tainted with secularism and frivolity as I described, and I do not know how much sense there is in it - after all, I do not think that a scholar of Torah would ever think about such matters on a practical level, and not because the law forbids it, but because it is clear that it is not relevant, especially not in our time. I do not know how objective and rather scattered I am in what I wrote, but just a point for thought.

You are mixing up the question of prohibition with the question of policy.