what possible reason could moderators have for needing to view deleted posts?
I'm not sure why nobody actually answered this part yet. I'll assume by "moderators" you mean "10k users", since all you need is 10000 rep to view deleted posts, you don't need to be a diamond mod. The reason 10k users can view deleted posts is they can vote to undelete them, as the natural counterpart to their ability to delete questions (just as 3k users can vote to close/reopen). They need to be able to see the question to know if they want to vote to undelete it
So not only is your post visible to 10k users, but if they vote to undelete it it could actually become visible to everyone again, which is why (as several other people have said) you should e-mail email@example.com and ask them to remove it from the database entirely