I believe you’re referring to the way some teenagers will brag about it covertly to their friends. Make no mistake, while on the surface it may appear as you say, that’s just the veneer of confidence they’re wearing that belies deeper inner turmoil. I won’t try to unpack what those turmoils are as they are different for everyone and I speak not as a psychological professional but as a professional educator.
What I encourage you to consider is the level of complexity people are burdened by and that when people with awful turmoil enter into your life, even just for a brief moment, that they should be first met with authentic empathy and care before cynicism as the stakes of treating these subjects with anything less are far too severe.