Why did the founders retain Slytherin's house?

[pippin_999]

No: HPFGUIDX 117828


Pippin:

> > Anyway, as I said on another thread, all the houses are 
racist.  It's just that the Slytherins carry the definition of
halfbreed 
a  little further. <<

Nora:
> Hufflepuff too, the Founder who said "I'll take the lot and teach 
all  of them"?  It seems that, if anyone, she comes off the best 
from the  Sorting Hat's Song in OotP.<<

Pippin:
'Fraid so. Unless "the lot" includes werewolves and mixed race 
children, who seem to be conspicuously absent.

 And what comes from the mouths of Gryffindor-educated 
children is hardly better than Draco's spouting, though indeed 
they'd never dream of saying things like that about Muggleborns. 

Hermione: "Don't trust him, he's a werewolf!"
Ron: "Get away from me, werewolf!"
Hermione: " I've never really liked horses." (referring to Firenze)

And don't let's forget the Fountain of Magical Brethren. And what 
about that citadel of apartheid, Hogsmeade, the only wizarding 
village in Britain? I wonder what happens if you're a Muggleborn 
Hogsmeade resident, and your Muggle mum wants to vist the 
grandkids -- or gets too old to live on her own. 

Also there's this, from JKR at Albert Hall:

JK Rowling:
When he (Harry) first entered the world (of Magic) he had of 
course expected it to (after spending time with the Dursley's) be 
this magical wonderland and almost immediately he wandered 
into Draco Malfoy in the robe shop and found out that Wizards 
are racist and slowly but surely he's found out that many people 
in power in the Wizarding World are just as corrupt and nasty as 
they are in our world. 
---
Wizards are racist. Not Slytherins are racist, or purebloods are 
racist. 

Pippin