If someone professes to believe in strict, materialist evolution then what Mr. Holyfield said must be truth.
Evolution has no purpose for anything, it just happens. That means sex isn't about pleasure or spiritual bonding or any other sentiment; it is only the means by which animals reproduce. That it happens to be pleasurable is only just another accident of innumerable chances producing an observed outcome.
Evolutionary theory would also be quick to point out that organisms that do not reproduce do not survive to successive generations.
If I may be so bold as to observe: Homosexuals do not reproduce on their own.
Thus, if materialist evolutionary theory is to be believed, homosexuality may exist but it exists in the same context as infertility/sterility.
Moreover, the Proglodytes refuse to acknowledge that homosexuality can be acculturated, i.e. ancient Sparta and numerous primitive tribes. It is one of the few disadvantageous traits that can be learned.
So, if we appeal strictly to observation, what did Mr. Holyfield say that was untrue?