There are American companies that manufacture and sell similar
outfits.Some of these have bloomers to the ankle, multiple layers, sleeves, etc.
Given the brevity of your post I'm not entirely sure what your point is, particularly considering the fact that America is never mentioned in the article.
I have no doubt that any American company that manufactures such items would be delighted to sell them to anyone on Earth, including the Kingdom of Sauidi Arabia or Indonesia where they would most likely be enthusiastically welcomed by the local culture and society, and their use would not represent a radical departure from local cultural norms and ethics as they do in Great Britain. Furthermore, if it is this American company that is manufacturing the items being discussed in this article which focuses on Great Britain, it is not they who are "instructing" the schools to change their uniform policy, and it is not they who are "demanding" that other wide-ranging, radical changes to accepted Western cultural norms be made in an effort to appease a highly vocal and frequently violent, steadfast and strident minority.