Do you think I got screwed, or is it just part of the hobby?

I tend to agree with this logic, I wonder if they forgot to do something such as what it says in my Mopar small block rebuild book, theres a certain little bypass valve just after the oil filter that routes the oil into the galley not anywhere else, it also went on to say, "Many people always forget to do this."

If they knew enough to remove that galley plug they should have remembered to put it back. And if it wasn't there then there would have been oil pressure issues.