According to this writer, it's because Obama has a character flaw of narcissism, which means he basically doesn't give a shit about anybody not in his economic/social class or those above that class.
In my view, his performance last night is a reflection of how he deals with Republicans in Washington. He doesn't really fight when attacked; he folds like a lawn chair. The reason he does that isn't so much to appease them than it is he truly is one of them.
Obama is the most right-wing president we have ever had in this country. The rich, especially those on Wall Street, own him lock, stock, and barrel.
This is not the Democratic Party I grew up with.