Assuming that African Americans (and Latinos, and women) don’t choose STEM majors because maybe they just want to be social workers and teachers is looking at the issue in a very narrow, superficial way. Not all choices are free and unconstrained and educated choices.
African American students may self-select out of STEM majors and careers because
-they don’t have any role models in science, technology, engineering, and mathematical careers
-they have less rigorous preparation in the area because of their high schools or because of academic tracking
-predominantly white and/or Asian science and engineering departments may feel like uncomfortable or hostile environments to them
-they don’t have a sense of the differences between “enough money” and “better paying”
-they’re being tracked into colleges that don’t offer good engineering and technology programs
or any other number of systemic reasons. So yeah, if you ask them point-blank they will say they chose their career because of X reasons (just like I chose my psychology major because I love the major and I wanted to help people). But poking around in their history or looking at the bigger picture may reveal some systemic pressures and reasons that are bigger than the students’ individual likes and dislikes. In fact, the student’s individual likes and dislikes may have been shaped and created partially because of socialization and systemic bias - my own career choices were constrained to things that didn’t require college prior to the end of my junior year of high school because I never imagined myself going to college until then. If a high school teacher hadn’t overheard a conversation and decided to intervene, who knows what I would’ve done instead?
However, I do take issue with the article’s lazy and inaccurate stereotyping of social sciences and humanities majors (“he does think that if a college freshman says she wants to major in psychology, a counselor needs to point out that she will likely also need a graduate degree to earn a good living” and “Part of the problem is that no history department wants to reveal that its graduates are working at coffee shops”, neither of which is largely true).