I agree. I think one problem is that things like "enjoyment" aren't as easy to measure as income or profit. It's possible to say that hobbies are rational by arguing that the enjoyment of the hobby outweighs the cost. But then it's also possible to say that people are willing to game the system (and take a financial loss) because they get enjoyment out of gumming up the works, and that enjoyment is worth the loss.