My entire undergrad schedule was arranged according to getting the best-ranking math teacher on ratemyprofessor.com. I had enough painful experience and had to early drop a math class or two to learn this fact. Bad math teachers essentially forced me to self-teach, and I did not have the ability to do that with math, as I wasn't a natural in math beforehand. It got so bad that I happily took 8am classes despite being a night owl.

What it looks like now as an adult is just a failure of pedagogy and institutional incentives. I suspect the people teaching it had little reason to take the teaching part seriously, it was just something that got in the way of their research/grad studies.

I went to a well-known state school. There were other departments like this.