Humans and animals are not equal. It's simple as that.

According to our laws humans have some rights by just being a human. Some animals have rights only because humans like them. Cockroaches have no rights because humans don't like them. Bear which killed human have no rights and will be killed to prevent more deaths, because humans don't like him. Cute kitten have a lot of rights because people like him and will be angry if they find out that someone tortures that cute kitten. Nobody will be angry if some kid tortures cockroach. It'll be disgusting, but that's about it.