JKR's intent.

[eggplant107]

No: HPFGUIDX 178773

 "delwynmarch" <delwynmarch at ...> wrote:

> Slytherin House is explicitely shown 
> to be the one House that won't oppose "evil" 

That is true, it is also true that some people (a lot of people
actually) do NOT oppose evil, but such people still need a house.
Remember there is a reason they are in Slytherin, and if they were not
allowed into Hogwarts at all, if they were not exposed to even a
little of the good side then they would end up doing even more
mischief when they became adults.

By the way, why did you put evil in quotation marks?  

> I still remember the horrifying moment 
> when I first read about Harry entering 
> the RoR for the first time in DH, and 
> noticing that there is no Slytherin 
> banner in it. [
]HP was not, had never
> been, this shining plea for tolerance 
> and understanding that I had once thought It was,

I do not believe it is outrageous to say that 25% of the population is
evil, or at least not very nice. Certainly it is beyond dispute that
the least moral 25% is less nice than the more principled 75%.
Everybody can't turn into a good guy and having a tolerance for evil
is not shining. 

The hat being a good judge of character sorts all that out. But I must
admit that despite the hat's claim that it never made a mistake
Dumbledore and at least this reader would disagree. I think Peter
Pettigrew was put into the wrong house, and Regulus and Slughorn were
not evil; Snape was not evil either, although he was not a nice man
and I wouldn't want to spend more time with him than I had to.  The
Sorting Hat is very good but not quite perfect.

> he [Slughorn] openly showed reluctance
> to even looking like he might 
> support the Order!

Yes Slughorn was reluctant, I'm reluctant to do something I know to be
extremely dangerous too; but the point is Slughorn overcame his fear
and even dueled with Voldemort personally! And if that isn't enough to
prove he is one of the good guys (even though he's in Slytherin) then
I don't know what is.

 Eggplant