JKR Interview on Mugglenet; Snape = Evil?

[pookasmorning]

No: HPFGUIDX 133730

I was blissfully reading the JRK interview that was posted on 
Mugglenet/The Leaky Cauldron, and came to a bit that has given me 
serious pause. 

***
ES: Was Dumbledore planning to die?

JKR: [Pause.] Do you think that's going to be the big theory?

MA & ES: Yes. It'll be a big theory.

JKR: [Pause.] Well, I don't want to shoot that one down. [A little 
laughter.] I have to give people hope.

[snip]

MA: 
whether this had been planned, and since Dumbledore had this 
knowledge of Draco the whole year, had they had a discussion that 
said, "Should this happen, you have to act as if it is entirely your 
intention to just walk forward and kill me, because if you don't, 
Draco will die, the Unbreakable Vow, you'll die," and so on — 

JKR: No, I see that, and yeah, I follow your line there. I can't — I 
mean, obviously, there are lines of speculation I don't want to shut 
down. 
***

I was completely convinced that Snape was a triple agent and that 
Dumbledore was pleading with him to go through with the murder. 100% 
sure. Now, however, I don't know what to think. That doesn't sound 
to me like JKR sparing our sensibilities; it sounds like the same 
sort of bet-hedging she did when asked about Harry/Hermione (and the 
same interview shows how that one turned out). 

So is that it? Snape wasn't faking it? Was this whole book just 
hitting us over the head with "Dumbledore is totally gullible, OMG"? 
Has JRK been playing with the readers' expectations regarding 
narrative conventions (i.e. the guy who seems bad must in fact be 
good) this whole time? Someone smart needs to weigh in; I need a 
cookie.

pookasmorning