I'd like to quote one of my favorite games called "Superliminal"
"Perception - is reality"
Is it amoral to fuck animals? For 90% of people, yes. Should you be ashamed of yourself? - you decide. You don't want to be? Then don't.
I've done quite a lot of shit that's considered illegal or amoral, but never hurt a good person or an animal. And if I was to bother about all of that, fuck I'd hang myself already.
Like, I'd kill a rapist or a pedophile with my bare hands but just because I myself see that as abuse that I don't like. Animal abusers there too, but not just people who fuck animals in a safe way.
The world as a default has no moral. It's people that come up with it to make life somewhat stable, but you're free to decide whether to follow it or not, just remember about the consequences of your very action (if it will be revealed) and you'll be fine.