No, there is ultimately worse he could have done. He's not leaving all crime alone, just the organised hits not endangering anyone. That's not evil, just desperate considering his situation.
People consider spidey 2 to be the best superhero film there and yet there and in superman 2, spidey and supes both leave their responsible roles for even less reasons, selfish reasons. Would you describe them as evil?
I don't personally think spidey's cynicism has to be related to his age, rather the situation he's in and the way he ways up the positives and negatives.
He's suppose to be a real character, he isn't right like captain america or wrong like the red skull but can do right and wrong things like the majority of us and when he's doing wrong, maybe he's not aware of it (some stuff he did to eddie), he's being influenced (by evil symbiote) or he's acting in desperation for a greater goal (kingpin offer theoretically). His whole persona is getting to grips with the motto his uncle gave him and how to bring it into practice effectively for everyone.