To be fair, Asians DO score higher than Europeans -- it isn't just some ploy to establish credibility. Anyone looking at SAT data can tell you that.
I would frame your objection a bit differently: finding an Asian IQ advantage is in no way incompatible with racism or white supremacism. Many of these guys (Rushton for example) believe that Asians are inferior in areas other than IQ.
I would say that most things are in no way incompatible with racism or white supremacism -- but that finding (and publicising) an Asian IQ advantage is incompatible (at least, for a white racist). But then my concept of racism might be different: I mean it to be any attempt to position members of some/all other races as inferior in some morally important respect, in order to justify treating them badly.
Do you know if Rushton's beliefs that Asians are inferior in other areas are based on experiments? I'd be interested in any links you might have.
I would frame your objection a bit differently: finding an Asian IQ advantage is in no way incompatible with racism or white supremacism. Many of these guys (Rushton for example) believe that Asians are inferior in areas other than IQ.