In defense of the Snape apologists :-)

[vmonte]

No: HPFGUIDX 136138

>1) Saving Harry's life in PS

>vmonte:
>If you recall Snape did not know that Quirrell was working for
>Voldemort during SS/PS. Voldemort kept Snape in the dark.

Mari again:
Let me expand a bit. The fact that Snape saves Harry during the
Quidditch match has nothing to do with quirrelmort and the stone.

At this stage Snape has no idea that Harry would be able to stop
Quirrell from getting the stone. Snape does not know that Harry is a
threat to Voldemort's plans to get the stone.

vmonte:
Mari I'm not sure what you are saying here? Are you saying that Snape 
knew that Quirrell had Voldemort sticking out of his head? If Snape 
is on DD's side why would he keep this information to himself? 

>Mari:
>2) Choosing to go after the trio to the shrieking shack, to protect
>them from someone he believed to be in league with Voldemort, in PoA.

>vmonte:
>Well, this is a matter of interpretation. I see a teacher that is
>more concerned with exacting revenge and getting accolades, than a
>teacher who is worried about his students.

Mari:
It's precisely because I can't see Snape being that concerned about
students that this action puzzles me. I totally agree that Snape was
after accolades. Later on in my post I identified this as a
characteristic of Snape's that is evident from what we know of him in
the books so far. He craves admiration. Let's look at the sequence of
events again:
1) Snape sees the trio (and Peter Pettigrew) sneak down to
Hagrid's on the marauders map.
2) He sees Sirius and the other four go past the whomping willow
to the Shrieking Shack.
3) Snape believes Sirius Black to be after Harry, and Lupin has
forgotten to take his potion so will also possibly be dangerous.

vmonte:
If Snape's main focus is getting Sirius in this scene, and not Harry, 
it makes sense, no? Snape has a very old grudge against Sirius and he 
has just found a great opportunity to exact revenge. He's saving 
Harry for the big Voldemort face off. 
And would Snape really think that Sirius was a DE? Wouldn't he know 
if he was or wasn't? I mean since he (Snape) was one. 

And why does he scream at the children to stop talking before any of 
them have a chance to explain about Wormtail? Is it because he knows 
that Peter IS a DE? 

Mari:
How could Snape have been blamed if Dumbledore thought that the Order
(including Snape) did not know what was happening at the Department
of Mysteries until it was too late? If Snape were just a death eater,
why wouldn't he have done all he could to ensure that Voldemort got
the prophecy? After all he is the one who told Voldemort about it in
the first place!

vmonte:
Because Snape was trying to lure Dumbledore to the DoM. Again, Snape 
is not on either side. He is trying to destroy both sides.

JMO