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.
You seem to believe that there's one consistent set of moral guidelines that separate people into wrong and right camps. This is not true, and most likely never will be true. Instead, there are many competing moral philosophies, many from hundreds or thousands of years ago, that do or don't encourage certain behavior. People tend to pick philosophies, or at the very least act consistently with some set of them, and different people pick or act with different ones.
Vaccines causing autism is simply false though, regardless of any philosophy. It's rather the inverse, much like violence can cause video games.