Question:
I read your response https://dinonline.org/2016/09/19/immodest-pants/ to the issue of pants not being modest for men.
But the correspondent who submitted this question complained that other rabbanim gave him beat around the bush answers, and now you are doing the same.
You agree that pants are not tzniut for men but you do not prohibit them as you do for women. Just as social pressure in the Hareidi society demands that women wear only skirts and men wear black hats, why doesn’t it, and its leaders, prohibit men from wearing trousers and demand that they wear masculine style dresses, as our ancestors wore before becoming negatively influenced by European culture?
Answer:
Please see the post again as it was updated, and should allay your concerns.
The answer that was given was that there is no essential tzniut issue with a man wearing tight pants, except for his own stimulation issue. It was not written there, that regarding other people it isn't tzniut. Men's pants are generally not that tight as described, and even if some are, it doesn't give a protruding appearance. The essential issue therefore is concerning the man himself, as was written in the other post.
In order to understand the halachos of tzniut, we must first understand that there is an essential difference between male and female hormones, and therefore halacha dictates that men have to be more careful about looking at women, and women about men looking at them, then the other way around. The reason why pants are prohibited for women is that seeing the shape of her legs, and the splitting of her legs, in itself is not tzniut and causes unwanted thoughts to men. This idea doesn't apply to the converse, to women seeing men, therefore pants are permitted for men to wear.
The reason why the hareidi community demands that women wear a skirt is not because of "social pressure" rather because of the dictates of halacha, see sources, and the following links https://dinonline.org/2018/12/30/rav-ovadia-yosef-on-women-wearing-pants/ and https://dinonline.org/2017/05/16/is-a-women-allowed-to-wear-pants-not-tight/.
Best wishes
Sources:
MInchas Yitzchok 2-108, Yabia Omer 6 Y:D 14 7,8.