That people's beliefs about X vary is not evidence that X itself varies. People have different beliefs about whether vaccines cause autism, but this doesn't mean that sometimes vaccines cause autism and sometimes they don't. Rather, some people are wrong.
Similarly, people have different beliefs about whether it's okay to inflict massive suffering on animals in exchange for some pleasure for us. But this doesn't necessarily mean that sometimes it's okay to do that and sometimes it isn't. It could just be that some people are wrong.
Ditto for other moral issues. It could be that the people who say (e.g.) homosexuality should be punished by death are wrong about this.
Similarly, people have different beliefs about whether it's okay to inflict massive suffering on animals in exchange for some pleasure for us. But this doesn't necessarily mean that sometimes it's okay to do that and sometimes it isn't. It could just be that some people are wrong.
Ditto for other moral issues. It could be that the people who say (e.g.) homosexuality should be punished by death are wrong about this.