See above comment and... Snape's bad choices let him to where he was. He chose being a Death Eater over genuine affection from Lily, but the mistake was made years before when he chose Slytherin over Lily. This is not to say that Slytherins are inherently bad, but he chose Slytherin pride over the one friend he had. Lily was sorted before Snape. The thing is he DIDN'T cling to her. He expected her to accept everything he did, but if he'd actually clung to her, followed her around like a puppy- he would have made more good choices. Maybe not the healthiest course of action, but healthier than what he ended up doing.

?He didn't know up from down or right from wrong. He was just thinking of himself in order to survive.

Survive? Like his survival was threatened by choosing Lily over hanging out with future death eaters? Slytherin over Lily? Mistreating Harry over at least being tolerable?

I don't see how Snape is not an asshole. I do think I understand his character. I'm not saying he's not sympathetic, but he's certainly an extremely spiteful and jealous, even cruel man. And he did care nothing about the death of a child, as the OP said.