You are slightly wrong, take the time to educate yourself and read the preamble on changes to training under a visa waiver that happened a couple of years ago, you will see they are a direct result of 9/11 ! You can search on pprune and find the info you need.
As I understood it any time of full time training, I think the number is > 18hr per week for anything, let it be a english course, or a flying course. Hence you can hour build in the USA, but little else without a student visa.
The large type rating school I went to put all students on a visa for their training when they were from overseas.