First, he is a socialist. America is a capitalistic nation that needs capitalism to survive. Currently, socialism is causing most of the problems in America (budget deficits, crime, poverty, etc).
Second, he disagrees with Democrat's JFK. JFK said "Ask not what your country can do for you but what you can do for your country". Obama says the opposite. Obama keeps telling voters lies about the free stuff they would get if he is president.
Third, Obama is fake. There are plenty of long lists of quotes that prove he is flip floping and making false promises. Basically, Obama is encouraging his followers to use "psychological projection" to make his followers believe he is good for the country. Lenin, Mao, Hitler, and etc. did the same to their supporters. (Later, most of the supporters regretted helping those people rise to power.)