Think about it.
The reason that every species has a built in desire to have sex with the opposite sex is to insure procreation. For that reason, such a sex drive is natural. If a species had a desire to have sex with the same sex, it would lead to extinction of that species. Therefore, such a desire is as unnatural as being born blind or developing cancer. It's clear that just like blindness or cancer, homosexuality is an unnatural and unhealthy state, for which we need to find a cure.
It may be a mental illness or it may be a physical disease. It may be a birth defect or it may be an acquired disease. But whatever it's cause, homosexuality is a sickness that needs to be cured.
If we just punish the sickness, the only thing that we accomplish is to drive the sickness underground, where it cannot be treated. On the other hand, if we cure the disease, there will soon be no offending act to punish.
It would seem that rather than continuing to punish those who have that disease, for years on end, it would be far more preferable to find a cure for the disease and be done with it, once and for all.