The problem with this attitude is that these same "idiots" also get called out when they follow their non-STEM passions in fields that don't have nearly the expected economic return that STEM fields so. Just watch any thread on college degrees/education.

What is a person with no interest or aptitude in STEM fields to do?

I always thought it was a good idea to major in what you love and then minor or double major in something that can get you a leg up in the job hunt. So if psychology is your thing, and you're really serious about succeeding there, do a second major in, say, statistics. That should give you a nice advantage in doing and interpreting research, and if you decide that clinical psychology or whatever isn't really your thing, being able to do statistics is a pretty desirable skill. You might not get a big data job with it, but it's not a bad investment.