People change, feelings fade, and only closed-minded individuals remain the same forever. In other words, instead of being too quick to judge someone's past behavior, remember the fact that you, yourself, were once somebody you'd consider wrong, naive, or different altogether.
I don't understand how people lose interest in learning new things. You mean to tell me you're at a point in your life where you're just like, "Fuck it, I know enough"? How is that even possible? Are you dead, dumb, or just lazy?