I agree with your sentiment. However, I do feel the need to awkwardly defend ad-clicks on a purely philosophical level.

While not a particularly impressive raison d'étre, connecting buyers to sellers is a legitimate market function.

This lies on contrast to several revenue generation tools employed by the financial sector. For instance, high frequency trading is practically indefensible and arguably destructive.

This sadly does not change the fact that a legitimate contribution is not necessarily meaningful. I'm curious to see what the legacy of our current tech boom will be.