That would require humans to have existed before religion, which is frankly quite ridiculous.

Are we supposing religious monkeys now? It wouldn't surprise me if earlier hominids were religious as well, but to call any other possibility "quite ridiculous" is really overstepping.

Not if you've ever met a human.

You don't think that there were humans that existed before any form of codified spirituality? I'd be willing to believe that explicit ritual bonding (marriage) didn't predate religion, but find it hard to believe that the first words we uttered went along with some sort of priestly social class or referenceable rules for living.

I don't know what the current state of research on this is, but I find it entirely plausible that rituals and social control existed before language.

Well, even creatures as low as termites and sardines exhibit mechanisms for social control - but it's not codified.

Why does it have to codified?

I do not follow?

It's not a very long sentence. What part is confusing?

It seems to me that the words 'humans' and 'religion' are inverted?

Not at all. Religion was born the first time a thinking creature looked up at the sky. Most likely some pre-homo sapiens hominid.