Its because Republicans and conservatives value western culture as superior to say black ghetto culture or central american culture. To 'liberals' culture=race, so they have to destroy and replace western culture to achieve 'equality'. This is why Islam is now a race, same with Judaism. The inability to admit that one culture is superior to another is one of the cognitive dissonance pillars of progressivism. This is of course shown by the list of 'white' traits like objectivity, rationalism, and independence which are now bad.