Because it is effective. Lying and cheating are low cost methods to convince other people that you have done the assigned task. Far cheaper than actually doing it. Coordinating is in the same area.

They need a moral framework forced onto them, like toddlers do. Babies and very young children will bite, kick, scream and do anything to get what they want, older children will lie, cheat, and coordinate. They need educating why this is not right. When that does not happen, they continue these behaviours into adulthood with the expected results.

We need to design their reward structure and make it such that lying. cheating etc is not rewarded. Importantly, they will need to recognise and enforce this themselves internally and not reward themselves for it. If it is something that they need an external party to tell them, then they are psychopaths still (one of the things that defines a psychopath is the lack of an internal moral compass)