It is really simple, Steve and Musket

A) make a list of significant differences between the illnesses as fairly as you can


B) Decide whether they add up to a reason to treat the illnesses differently


I have decided that my answer to B is that the differences are insufficient to treat the diseases differently: both should allow condom use. But I don't think the list from A is empty and I can see why someone might regard the differences as enough.

As for writing the list both Steve and Musket are intelligent enough to come up with their own versions