It depends on the somewhat elusive definition of "human."
If you mean, "Human beings do indulge in perversion," then: too, too true. If you mean: "This behavior is still within the norm for human beings," then it's false.
If Ryan meant, "Homosexuals are not human beings," he was wrong, and his statement is deplorable. If he meant, "Acts of perversion are beneath human dignity," he was right.
In any case, all I saw was the one line about "Homosexuality is (not "Homosexuals are) subhuman," and, while ambiguous, it seemed to be referring to the behaviors, not to the human status of the individuals.
Why didn't the concerned officials of Duquesne just write him a letter and ask, "What do you mean?" Or let him assemble a panel discussion on the subject.
That might arguably be related to the purposes and methods of "higher education."