Um, we are apes.

Bestiality is a moral judgement call; if you can establish consent, there's no harm. We rule it as deviant because it's weird and gross, not because it's harmful.

At the point we can breed two animals and yield a progeny, it's no longer interspecies, and would [no longer] count as bestiality. There's a gray zone, like breeding horses and donkeys to make mules. But then we do that because there's an economic benefit, deviance be damned.