Reason Dumbledore trusted Snape

[pippin_999]

No: HPFGUIDX 171702

> Magpie:
> Harry is a Half-Blood because his mother was Muggleborn and therefore has
> "Muggle blood." I agree this is one of the most confusing things in canon,
> particularly since Draco, who is in some ways our mouthpiece for this sort
> of thing, never once has a problem with Harry's bloodline or insults his
> mother.

Pippin:
Oh, but he does. 

"Or perhaps," said Malfoy, leering as he backed away, "you can 
remember what *you're* mother's house stank like, Potter, and
Weasley's pigsty reminds you of it--"

OOP, ch 19. 

Malfoy and Voldemort use the term 'half-blood'  loosely,
so does Hagrid, and even Dumbledore, for that matter ("he chose, 
not the pureblood [...] but the half-blood, like himself") underlining 
the fact that their purpose is identity politics, not science.

Pippin