Dean knew how gods were. In his experience, they were selfish assholes with absolutely no empathy, so he was extremely unhappy after Castiel told them about a god/goddess in Michigan (or whatever your choice is :P). Yet, they still had to check it out. Even if there were no recorded cases of harm in your area, Sam and Castiel thought it wouldn't hurt to check. Nothing could've prepared them for what they were going to see, though...

Just as Sam, Dean and Cass arrived at your house, which was standing in a forest kinda far from civilization, they saw you sitting at the river, a baby deer in your lap, a cat laying cuddled up against you at your side and a kid laying a few meters away on a small blanket. Dean didn't expect this. Not at all