It is because you read the translation that intentionally translated them into obscure hard to understand and interpret language. So that they poem feels more ancient and "serious" to reader.

But originally they were written in the language of the time and in the way that made them easy to remember for contemporaries. They had rhythm, because that is easier to remember. They contained a lot of repetition, because that is easier to remember.

It wasn't that long ago that books were so rare/valuable/difficult to have access to that folks would read and memorize pretty much everything they could lay their hands on.