I didn't read anything wrong. I have a GenealogyBank membership, and I DID A SEARCH and found nothing in historic newspapers or historic documents. David Sizemore was not alive late enough to be issued a Social Security number, so you will not find him on the SSDI. Just trying to save you a little money.
I wasn't being rude, I was trying to help you by explaining to you that most of the documentation you need in order to properly research your genealogy will not be found online.
I've been researching my genealogy since 1990, so I know a little bit about research. Not to say that I know everything, because I don't. But on this point, I am positive.
I read another of your posts where you said something to the effect that you wanted your tree to be factual. Limiting your research to only online resources will not accomplish that. At some point, you will need to write a letter, make a phone call, or visit an actual building or cemetery.
I see that you've only been working on your tree for a couple of weeks. Here's a tip: When someone who has been doing this for many years tries to give you some helpful advice, listen. Many of your posts on other boards have been snarky and rude. Bite too many hands, and you will find that no one is willing to help you at all.
Re-read the things that I suggested (especially the OFFLINE resources), and I guarantee you will have an easier time finding information on your ancestors. Once you get the actual vital records, you will likely find that at least some of the information contained on your census records is inaccurate.