Religion is not the only moral excuse, vegetarianism, fruitarianism, and other secular things are morally an excuse. By pretending to be better behaved is the simplistic behaviour of acting religious by placing the present time above yourself what you used to be (placing yourself above your usual self). You tell mummy you didn't do it because you invented your own religion, so you must be good, then mum tells you you're good so now she thinks being a priest is good. And she questions you and you show no proof that you did it so you truthfully say "if I did it it would be unholy, thou shalt not do it". Yes, religion is a moral excuse, especially an invented religion (to know about invented religion as a moral excuse, read Jesus making excuses to do a religion no one followed when he made excuses). It only exists to appear good to your mummy, it's there to get attention.