I think it's more that they're considered impossible to judge, and so they kind of get passed around with a blank "Hey, have you ever heard of this place?" Ironically, I think you do better if you're from China. There's enough Chinese immigrants to educate you about Chinese engineering schools. Europe is just too diverse to build up this

Either way, you end up not looking at what foreign school they went to, but rather what graduate program they got into in the US.