Euphemisms:
I agree, the context of 1Co.6:9 seems to make this a clear euphemism for homosexuality. Euphemisms were often used in scripture for this behavior.
(It is interesting though, and telling, that it uses this particular euphemism.)
We also have some clear prohibitions against things like cross-dressing. And when we see those passages, they too have the connotation of homosexual conduct. So the problem with cross-dressing is a lot deeper than WHAT you are wearing; the real problem is WHY you are wearing it.
Cross Dressing:
It's principally an issue of intent.
If your wife puts on one of your manly shirts, it's probably not because she wants to be a man.
It's probably because your shirt is comfy, and cozy, and probably makes her feel secure... it makes her think of you.
She isn't trying to be a man.
Now, if she was wearing all your clothes, along with drawing on a mustache, and she was roaming around pretending to be a bloke... then you'd need some counseling.
Apologetics & Debate:
So if we remember this is all about INTENT, then we're armed to fend off all the attacks from progressives trying to justify cross-dressing by bringing up men in ancient times wearing skirts or long robes. A man in ancient Greece may have worn something like a skirt, but it was still a "man's" skirt, and something appropriate for a man to wear in that culture. If he was TRYING to look like a woman... then that was a different matter.
(Note on Ancient Greece:
Despite all the progressive re-interpretations of history, not everyone in ancient Greece was gay, and it was not something the majority participated in, and it was not considered normative. In reality, their entire view of sexuality was so different than modern culture that they really didn't have a concept of men who ONLY had relationships with men. Homosexuality did exist, as a behavior, but they had no equivalent to the modern concept of "gay" as either an identity or as an exclusive preference. Modern views simply don't apply to the ancient world.)
.