Yes, you really do.
Gang culture, mob culture and criminal culture in general is very commonly misunderstood. This because media regularly romanticize the lifestyle of these people giving us the public a poor understanding of how these groups actually operate and interact. Not to mention the countless former criminal talking heads who spit bullshit about the former life they lived on TV and youtube.
This leads to a misunderstanding of criminal organizations and quite frankly paints them all with incredibly broad strokes. The truth is, not every Crip or Blood set operates and acts the same. Mexican gangs, specifically sureno gangs have a whole different culture then they're African American counterparts, these organizations are not the same and to lump them together and say "Gang RPers should do this or Gang RPers should do that" without understanding the specific history and culture behind each individual gang is quite frankly, moronic.
I'll close with your argument about 14/15 year olds RPing fear. It is very important to understand that these children grow up in an entirely different world then I'll assume you or I. They have grown up in a community where violence is the norm, a community where most of the big names coming out of it have a criminal past. Wrong or right, these individuals are looked up to and the stories they tell only influences the minds of the younger generation. While many of you are right about how the "OG's" of the 70's, 80's and early 90's wouldn't settle ever dispute with a gun. That does not change the fact that shootings have quickly become the preferred and almost sole tactic to handle disputes.
At the end of the day, all those kids are trying to impress or at the very least not look weak in front their friends. This is they're life, this is what they grow up around. The sad truth is, the quickest way to become billy bad ass on the block is to shoot somebody. Plain and simple.