White supremacists are fine with "lesser races" be subjugated and "taught their place" under the rulership of their "true masters". Practically none of supremacists want to exterminate other races - only to take superior position over them. Which matches the position of Islamic supremacists - you can live under Islamic rule (either as Muslim subject to Islamic authority, or as infidel recognizing Islamic law supremacy and bowing to it) or die.