That's the curse of free choice. People choose things that draw them in not the things good for them.
They choose sweet and salty fats in the real world and they choose things that make them feel the strongest emotion online. The system based on consumer choice delivers.
There isn't some evil mastermind behind it--at least, in the click-case; in the psyops or vote-for-us! cases there might sort of be, but even there they aren't profiting from the misery per se.