I've taken 2 required critical thinking courses from 2 different state schools. They were in the philosophy department. Why do you think they don't teach it? In stanford, for instance, they require taking 2 courses on formal reasoning as a prerequisite for a degree, which invariably includes critical thinking.
There was a critical thinking requirement that multiple courses fulfilled. One was a critical thinking english class that involved a lot of writing. I didn't want to write, so I chose the philosophy course (which still involved writing).
Here is a state school that has a foundation requirement in critical thinking with several courses:
https://www.csulb.edu/student-records/ge-approved-courses-ca...
Yes, but, thinking critically about this, why would learning how to hand-weave on a loom teach critical thinking? I get that you weren't doing these courses at Stanford but it's this kind of thing that makes people skeptical when universities make grandiloquent claims. Stanford is supposed to be the gold standard, so when it makes it appear that they teach critical thinking but actually don't (or it's at least very easy to make choices that won't do so) of course the claim is devalued.
If universities really cared about this aspect of their reputation they'd defend it by firing professors who were found to not be thinking critically e.g. by praising or putting their names on papers that are clearly fraudulent. It doesn't happen.
Your original claim was "there is no evidence to suggest this is true (teaching critical thinking)". I presented my own anecdotal evidence, and then a counterexample. I'm sure there are many, many more. Moving the goalposts is not a discussion I'm interested in having and you seem to have a very set viewpoint on this topic.
I've never heard of anyone being required to take a philosophy course but some universities surely do it. I was curious about the Stanford claim. This is the Ways system, right? Their website says you need to take at least one course in formal reasoning:
https://ways.stanford.edu/about/ways-categories/formal-reaso...
They list a few examples like market design or programming. I thought, OK, formal reasoning maybe, but is that really the same as critical thinking? Then I clicked the "See Formal Reasoning Courses in Explore Courses" link:
https://explorecourses.stanford.edu/search?q=all%20courses&v...
143 courses are considered to teach formal reasoning. First on the list is "The Questions of Cloth: Weaving, Pattern Complexity and Structures of Fabric (ARTSINST 100B)" which teaches hand weaving on a loom. A bit further down there is "Introduction to Bioengineering" which teaches "capacities of natural life on Earth" and "how atoms can be organized to make molecules". It goes on like that.
I dunno, this doesn't sound like anyone has to study critical thinking specifically to pass the formal reasoning requirements. It sounds like almost anything connected to science or engineering in any way counts. And that's Stanford!