The guy was a responsible kid who liked who he was the way he was at one time, but he tried to loosen up and live on the wild side because he thought he might have missed out on something, and ended up being certain that being a poser wasnt for him, he tried it, so he knew it was all done to get money while telling people you dont care what they think even when you care more than anybody else what people think. Everybody cares what people think, and that's one of the things you end up facing no matter how long you keep telling people you dont care what they think. You end up facing them, and they end up facing you.
When someone's really uptight and generally being a humorless or overstudious person, you'd say this to them to indicate that they need to relax and take themselves less seriously sometimes. A kinder alternative to get over yourself.
"Why would you play that game? It's so violent and misogynistic!"
"Wow, what are you my mom? It's just good mindless fun, loosen your collar. Damn!"