BTW, that is an incomplete quotation of Aquinas (and keep in mind that Aquinas is a brilliant theologian, but not infallible and not the Magesterium) who said (in his day):
As stated in the foregoing Article, outward apparel should be consistent with the estate of the person, according to the general custom. Hence it is in itself sinful for a woman to wear man’s clothes, or vice versa; especially since this may be a cause of sensuous pleasure; and it is expressly forbidden in the Law (Dt. 22) because the Gentiles used to practice this change of attire for the purpose of idolatrous superstition. Nevertheless this may be done sometimes without sin on account of some necessity, either in order to hide oneself from enemies, or through lack of other clothes, or for some similar motive.
When you are cross dressing for arousal: can be sinful
When you are wearing attire normally worn by the other sex for other reasons: not sinful
Outward apparel should be consistent with the custom:
In the US, women wear pants made for women, and men wear pants made for men.
In Muslim countries women wear long skirts, and men wear robed attire also but they do not wear the other sex’s attire.
Now, stop looking for what is not there in Church teaching.