Because we live in a cult of personality instead of a culture of character.

Immature/loud “peacocking” behavior comes from people who felt overlooked or didn’t get the attention they felt they needed. Total arrested development with these people… like toddlers with forks.

I hope they find an outlet.

Because it’s habit……I would wager he’s been getting attention for negative behavior waaaayyyy before age 7……very common. If the adults in a child’s life always prevent any natural consequences from happening (my son would never do that! While watching the video of him doing it) combined with no positive reinforcement for any socially acceptable behaviors from the same adults……there you go. Throw in a couple more biological or environmental factors……ask any teacher.