Silo appeared to be bisexual, but Roy was only interested in two males, one being Silo.
You do have a point though. For example, make cane toads will literally mate with anything they think they can mate with. Like soda cans. They don’t even see, to consider whether what they are humping has something for them to stick their cane toad penis in. Honestly, it’s amazing they breed so prolifically in Australia despite the lack of predators because they’re clearly very stupid.