For whatever reason, many University programs use high level math classes as a filter to weed out 1st year students from that program. If university instructors had a genuine passion, and ability, for teaching high level math then they wouldn't accept that as an outcome.
You are misrepresenting what's happening. Other departments use beginning math classes as a way of weeding out students they feel won't succeed in their fields because they can't pass basic mathematics classes. Most math departments would absolutely love to have more students in them.
The problem is that these students aren't prepared properly by K-12 mathematics courses and math builds upon itself. If you don't have a good grasp of algebra, you just won't succeed at calculus. We're sticking people in the equivalent of Spanish 4 without having learned Spanish 1 properly.
That is unfortunately true; not only in the US, but all around the world. The particulars do depend on the instructor, and many if not most instructors try to be motivational, but the syllabus is perfectly clear: "this is a weed out class". And when it comes to test time, the syllabus wins.
The only thing I disagree with in your comment is about the instructors: they want to be employed, and they have to accept the syllabus and testing standards. It is not about passion and ability to teach (most, especially younger ones, are full of those); it is about meeting the departmental requirements.
Except maybe not calculus. I remember my calc class kind of being terrible because it was a weed out for other majors. Every math class that wasnt required though was great.
