The racist behavior of Centaurs

[severusbook4]

No: HPFGUIDX 75250

Since everyone is ranting about the so called racist comments of 
Hermione and Hagrid, I though it fair to point out that in the book 
Centaurs are the most racist of anyone in the series.  In SS Firenze 
is berrated for giving Harry a ride back to Hagrid and friends.  In 
OotP, Firenze is attacked because he is working for DD.  Having 
anything to do with mere humans is enough to get a centaur banned 
for the herd.  A centaur can be punished for trying to save the life 
of a human, so it would be agreable to the herd to let them die?  
This is serious supremist behavior if I ever saw it.  So cut 
Hermione and Hagrid a break.  It seems that centaurs might deserve a 
little racism thrown at them to knock them off their high horses, no 
pun intended.

Ron said there wasn't a wizard or witch that was bad that didn't 
come out of Slytherin, does this make him racist towards the house 
and occupants of Slytherin?  If we are casting stones at who has 
acted racist, let's not forget anyone.