While I agree with most of your post, I think as far as funding is concerned, they treat non-resident Americans and international students in a same way. Yes it's more economical to fund state resident students but non residents have same tuition fee as international students in most cases. And funding is usually tuition waiver + stipend (sometimes medical insurance isn't granted) which is same for both international students and non residents.
Moreover, in my program (ECE), majority of the current students are international students in Texas A&M.
However, I concur that unfunded offers should be treated as a rejection.