Most school curriculums nowadays have critical thinking interwoven as important parts of the STEM classes, in both primary and high school. Its not exclusive to college graduates, however if you do a philosophy course then you will have learned the highest level of it - and I’m sure many school systems around the world have varying degrees of quality of education.

But agreed it is absolutely something that people are not born with and must (and should) be taught.

Sorry but that is wrong. You are using the textbook definition of confirmation bias.

Critical thinking “is the process of analyzing available facts, evidence, observations, and arguments to make sound conclusions or informed choices. It involves recognizing underlying assumptions, providing justifications for ideas and actions, evaluating these justifications through comparisons with varying perspectives, and assessing their rationality and potential consequences.”