he said "it's really shameful". "making fun" is not the right word, but he clearly was attacking the actor for it.
True. "Making fun" is not the right phrase, as that would imply there was humor involved. He's not being funny. (And I changed my post above, in which I originally used the phrase too, accordingly.)
I guess what Rush Limbaugh actually did was accuse Michael J. Fox of
lying about his own progressing and degenerative disease. After listeners reported to him that Fox's symptoms are genuine, Limbaugh apologized for the original accusation and substituted a new one, accusing Fox of
exploiting his own disease as a political strategy to mislead voters.