I'd say it wouldn't - I just heard from one (a very nice person, btw) who insists we don't have enough information to judge Snape's motives about anything. I think we do - the information is there, just as it was there about Snape's poverty and his ancestry - but it is subtle, and certainly not complete. But, like other Sirius fans, she doesn't seem able to see Snape in a positive light, no matter what the evidence.

Glad you liked this, though! One thing the Sirius fan said was true; we really don't have all the evidence yet, so we cannot tell for sure what Rowling is doing with this character. But I will be SO THRILLED if I am right!