5th dnd – Wait ….. Fireball is not an attack?

I am stunned. This has been covered by the wise advice, because it seems to be a desperate need for an injection of common sense. Could anyone explain how this became the decision for Fireball?

Number of people making this statement in the subtle spells thread. They say that because Fireball does not have an attack roll, throwing it is not an attack. The rules of the hidden adversary do not apply and do not reveal you. (Which seems very false to me).

Of course, a fireball is an action of attack, not an attack. But … Do not we ridicule the hair when we conclude that throw a fireball on someone's not an attack?