None of them were competent enough to make an informed decision insofar as the leadership of the nation because they relied on faulty analysis, willful ignorance of Donald's many flaws, and self interest in lower taxes.
I'm not sure why this is controversial. The average college educated individual is presumably skilled in their profession but their profession but that is hardly sure to inform their understanding of matters out of scope of that profession.
Do you find it surprising that 30% of any group makes poor decisions?