Then why is something assur. Is the original assur of beged isha so that men don’t end up mingling with women? Or, what? It’s easy to just declare something assur, but there has to be a reason for it unless this considered a chok.
It doesn’t seem to me that the Torah wanting men to be men and women to be women would be a chok.
The meforshim do talk about a concern about arayos, but that’s only one aspect of it.
According to the Chinuch the main reason of the issur (wearing clothing of the opposite sex) is to prevent male/female mixing.
But as discussed, the poskim extend it to other areas, clearly to treat men and women differently and thus create boundaries that prevent pritzus.
I know frum men who go to nail salons. I have an issue with that. It is inherently a place reserved for women and thus against the spirit of the halacha.
Obviously societal norms play a role. If a frum Scot wore a kilt, that would be mutar. I would even guess that we may allow a frum asian girl in vietnam to wear those baggy pantaloons. (since they are tznius and the norm)
The question is, “how long does it take for something to be considered a societal norm before the halacha may change?”
I personally would want it to be universal (and not something inherently pritzusdik). If all american guys colored their hair then maybe I can see a posek reversing a previous opinion. But I may be wrong. It could be that once something is assur in a society, we don’t change it. (ie lo-plug)
Rashi in this week’s parsha on lo silbash specifically say the Torah assirs clothing that can lead to toevah. So my point stands, why is so extended to areas such as hair coloring? What was the concern? It’s easy to just assir things.