Extra humour is provided not just in the dressing up, but in mocking the more extreme forms of femininity which are forced down girls throats via all of our media, and through social approval. Clothing with high heels, makeup. Big hair. Exaggerated mannerisms >> giggling, stance, and so on. So on the one hand, they are aware that this is how girls and women are "supposed" to be, on the other hand they know that this is mocked. Difficult one to navigate.
Yes, if anything that is what drag queens are mocking, societies pereception of femininity, the expectations of how women should behave, not actual women and what it means to actually be a woman.
None of those things you mentioned a part of being a woman at all and drag shows that, male drag queens can do all that and still be male. Have you every spoken to a drag queen and learnt about drag? or just been offended and cut them off? I think you would be suprised.