Imagine if such a couple lives on your block and your child will come home and ask you, look what a nice loving family why is it wrong?To say that the Torah forbids it when your child might see that they seem very happy is a very hard lesson.
Imagine if a cheeseburger eater lives on your block and your child will come home and ask you, look what a nice looking cheeseburger why is it wrong? To say that the Torah forbids it when your child might see that they seem very happy is a very hard lesson.
As per the OP, is Hedonisim immoral? Perhaps not, especially without any oncept of morality (which is intrinsic to Hedonism).