It’s so anti-woman to say she never worked. The PC and more accurate thing to say is she never worked outside the home but in Betsy’s case I’m sure she had a staff of workers who helped her with her charities and advocacy. I guess what they mean is that she never drew a paycheck.
Judging from the rest of the sentence, I think the writer was trying to say that Ms. DeVos never worked in a public school.