The fact that everything is valid when put to a vote is why that stuff can change though, rather than saying "No no no, GOD wants slavery, so you can't just 'vote' it away, that's blasphemy."
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FTyranny_of_the_majority
If that was true, we wouldn't need a constitution. The current popularly elected government would be right about everything.
And in the US, nobody "voted away" slavery. There was a big war about it. It was a whole chapter in your high school social studies textbook.