A person can take being an "adult" too far, however. They can say that anything that doesn't help you earn money is a waste of time, that anything creative is also a waste of time, and chase status and money. Maybe many of these people got burned at some point for being childish (e.g. they were criticized by a manager or partner and made to feel shame), which explains the behavior.
It depends on your goals, but a nice moderate view is to discard with the labels, and aim to be responsible and have self-control, while also being curious and open to creative pursuits. It's also great to enjoy whatever media you like without caring about what others think (whether it's obscure or mainstream).