Obama believes in capitalism, something that is not acceptable for a socialist (even though it is acceptable for me as a social democrat)
Obama believes in private ownership of companies, socialism does not believe in private ownership of the means of production
Obama does not believe in planned economy, whereas a socialist does
Obama is a Christian (not a Muslim) and that is also not in accordance with socialism (Marx said that religion is the opium of the people)
Obama is not a centrist democrat, but as a social democrat I am considerably to the left of him and socialists are miles to the left of me.
Also, what does this have to do with having a cross around your neck?