Doesn’t the “good deed” require punishment?

Growing up, I was always told to do good deeds so that God blesses me with ten times as much. Now, maybe my parents, family, teachers and who have you advocated this cost-benefit analysis system so that I grow up to be a conscientious adult, but now that I’m a thinking, (almost-) functioning adult of 19 years of age, this system seems to me more and more problematic.

Let me break it down. 
First of all, children are more adept than we give them credit for. They are amazing are deducing patterns, thinking critically (I hold the belief that the education system is responsible for stifling the creativity and critical thought in children) and dealing with rationality and logic. So when we establish to children that morality comes with self-serving strings attached and incentivise them to ‘be good’ only to better their own life, we’re essentially nurturing the notion that we must look for profit in every action that we do, which saddens me. 
Secondly, the ‘good deeds’ that the child is instructed to do never talks about the other for whom the deeds are being done, focusing once again on the child in question. What this does is create a logical thread in the child’s psyche that focuses on a reward system, wherein the child (much like a cat in the Skinner box) does a good deed (by pressing a lever) and guarantees themself a reward. The benefactor of the deed in this particular equation loses their humanity, they become a mere stepping stone in order for the child to receive their reward.
Perhaps the most disheartening of problems with this logic is the way we defend morality lessons such as this one. I’ve heard one too many times that performing good deeds as ends in themselves is too abstract a concept for children to grasp and so they must be fed the bottom-line with just a hint of a bribe in order for them to uncover the morality of it on their own. This argument not only insults children’s ability to empathise but also excuses the fact that adults in this society would rather find a heuristic to teach their children how to be moral than actually explain morality to them the way it is meant to be taught.

I’ll leave you with this question. How is it that it widely-accepted that children’s minds are like sponges and yet, care-givers would much rather stifle their potential with algorithms instead of teaching them not what but how to think?