It's somewhat nuanced. You're missing the human aspect of it. If someone tells you an action is mandatory, it implies that they have some sort of power over you

It's somewhat nuanced. You're missing the human aspect of it. If someone tells you an action is mandatory, it implies that they have some sort of power over you (boss, police, government, etc.). If someone tells you something is required, it has more of an air of "you need to do this to access this product".