As if it isn't obvious why...
Actually, it's too obvious why that most people don't even realize why men shouldn't wear women's clothes.
Think about it for a moment.
Clothes are designed around the shape and form of the human body.
Problem is, there's a lot of types of human bodies out there.
But by and large, you can smoosh it into two categories:
Feminine and Masculine.
You see, men like tits, ass, and jiggly bits.
We just do.
Some like petite tits, ass, and jiggly bits. Others like huge badonkadunks and badonkers.
And women, being the jealous things that the are, will try to one-up each other simply by nature.
Women are always comparing themselves to one another...
So it makes sense that eventually they will try to modify clothes and makeup to both A: Over-emphasize what they do have going for them, and B: Do things to bump up what they lack just a smidge.
Tada! Make up and fashion are born.
And men are more than happy to help women endeavor to look aesthetically pleasing.
Sometimes, however, they really gotta think outside the box...
https://www.malaysiamarketing.my/wp-content/uploads/2020/03/a2c0-1050x600.jpg
But, by and large, women's clothes are designed to accentuate what physical traits men want in a woman.
Enter, drag and trans monstrosities...
You see, a masculine body simply doesn't have tits, ass, and jiggly bits nor the hourglass or hourglass adjacent body form that feminine clothing is designed around.
So, when you put a woman's clothes on a man, it looks wrong. It looks weird. It looks like a joke is being made based on the magic that is juxtaposition.
https://www.youtube.com/watch?v=fbQqnJw7xL0
You see, the reason the British in particular had a big stint of laughing at men in woman's clothing is because the joke was juxtaposition, and the British love juxtaposition.
That's not supposed to be there! LOL!
And it is juxtaposition, because you can slather all the frosting you want on an onion, it still don't make it a cake!
That's what's happening with feminine clothing on men.
Men are like onions. Stinky, they have layers, make you cry sometimes, and if their juices get into the wrong cracks you might just regret it... and then cry...
Women are like cakes. They look fantastic, cover themselves in all sorts of decorations, taste and smell good especially when heated up, and are super sweet despite sometimes their flavor not being your favorite. They come in all sorts of shapes and sizes, and a lot of work goes into how they look.
BUT!
When you put frosting on an onion, that don't make it a cake!
It takes an onion, whose purpose is to be a base for cooking umami flavored things and round out the flavor of slabs of meat, and simply turns it into something disgusting.
So, when you see a trans person or a drag queen, you're SUPPOSED to be disgusted.
Because it's disgusting...
Like an onion covered in cake frosting.
It should be laughed at and ridiculed because of the juxtaposition.
But not eaten until you wipe off the frosting trying to be somewhere it really, fundamentally, should not ever be.
Then again...
Women CAN wear a man's clothing and it not be a problem in most cases...
Why?!
Because 99% of the time men's clothing isn't trying to accentuate features. They're actually trying to A: Hide the undesirable body features or B: Show how much money they got so the wamens know they can support her and her babbies.
So, by default, a man's clothing is primarily functional and isn't always tailored to create a bodily illusion.
To compare, women get dolled up like a company logo -- to be striking, appealing, and immediately identifiable.
Men are like bathroom stall signs that need to be clear as to where you'll end up through the door because the brown turtle is about to come out of its shell and you really can't spend time pondering when you have to see a man about a dog.
A logo can reduce detail and still be recognizable as a brand logo, but you can't reduce a bathroom sign anymore than stick figures, and you definitely can't overcomplicate them because this sort of crap happens:
https://www.youtube.com/watch?v=8nFn9qQ9swk
With all this being said...
I think the whole thing is summed up pretty well on its face.
When a man wears a woman's clothes, it just looks fuckin' ugly and disgusting.
TL;DR: Men shouldn't wear a woman's clothes because they have none of the bodily features a woman's clothes are specifically designed to accentuate.
William Wallace wore a kilt and that dude weilded a 6 foot claymore!