Hendry concludes that strikes by university faculty should not be permitted. This is because strikes by employees shouldn’t be permitted if they harm the employer’s customers, and faculty strikes harm a university’s students. Hendry also acknowledges that most employee strikes should be legally permitted.

Menkin says that if Hendry’s principle (strikes aren’t permitted if they harm the employer’s customers) is true, employee strikes should almost never be legally permitted.

We’re looking for a point of disagreement. They disagree about whether most employee strikes harm the employer’s customers. We can infer that Hendry believes most do not, because he believes most strikes should be permitted. Menkin believes most strikes do hurt the customers, because he believes most strikes shouldn’t be permitted if we accept Hendry’s principle.