The level of pride in being American that Democrats have by and large is still a kind of nationalism, albeit surely a more nuanced and conscientious one than the ones Republicans have (again by and large). Can't comment on which side is actually better for the country (that's politics), but my point is that Democrats (and allied liberals) are hypocritical in the sense that their pride is supposedly healthy patriotism while another's pride is 'nationalism'.
Ultimataly both Democrats and Republicans are sustained by extensive sales pitches of what America (TM) is all about. Democrats seem to think their politics represents the One Final Political Solution to End Misery Everywhere, but it is still based on aforementioned sales pitches all around ("We're on the Good side!").