Morality is simply the way that an individual chooses between opposing values in a given situation.
So, lets say "Prolife" vs "Prochoice" as a moral issue. Regardless of your position, you are pushing values. The question isn't "is a fetus valuable?" or "is a woman's right to choose what happens to her body valuable?"
The vast majority of the world would answer yes to both. No, the question is... "which is more valuable if you can't have both?"
In this way, morality requires an active decision making.
This is where I think you are right, but incorrect. Right in that your objection is excellent. Sparknotes did write over this key point too briefly and with too much assumption. Right in that Camus is CERTAINLY propagating his values and morals through Mersault.
Incorrect because Mersault himself is a puppet. He is not and could not be a human being. He himself does not make conscious decisions, but rather passively allows things to happen with, to, and through him. Because he never begs the question of value, he cannot possibly be considered moral. Decisions themselves are not moral, only people are.
In the end - sparknotes was Wrong and correct, and you - I feel - right and incorrect.