A few points:
1) I've never met ANYONE who is your "Bob".
2) Obama is NOT liberal, he is Progressive. The Uber Progressive in fact, the antithesis of liberalism.
3) The folks you describe here are typically the TRUE conservatives. The believe in limited government. Not just limited government where YOU want limited government, but across the board.
As a result, they believe that social issues are primarily the responsibilities of the States, or, at the very least. none of YOUR business. i.e. Individual LIBERTY. The freedom to be socially liberal OR conservative.