The claim was that a math degree is easier for making the switch than the opposite switch: e.g., an English major would likely do as well as a math major in get

The claim was that a math degree is easier for making the switch than the opposite switch: e.g., an English major would likely do as well as a math major in getting a law degree, but would find it nearly impossible transitioning into mathematics without the equivalent of a second BS. I don't think this is particularly controvertial.