I’m not defending Holder, but these remarks were made in the 90s at the height of the gangbangerr culture in cities. These were the days when a kid was being killed or wounded in NYC every few days (before Rudy). Having a “9” was a symbol of success and power in the hood. So people like Holder believed they had to change that image and make guns less attractive to the teen males in cities. It was not, at the time, aimed at the guy who’d take his mini14 to the range or the fields twice a week and fire off ahundred rounds. It probably is today, but when a person’s words from 18 years ago are used to argue against them today context matters and in this case Cupp got the context, if not Holder’s beliefs, wrong.
He was speaking of the shaming of cigarette smokers as to what should be done to gun owners.
Holder's fundamental proposition is that gun owners should be shamed. If we accept the argument that in context this means 'urban teens murdering other teens' as you suppose, we are still left with the original question: Why did Holder believe that a person who is not "shamed" by the murder of another human being would be "shamed" by the ownership of the weapon by which this was accomplished? For those who had not committed a crime, why did Holder believe that a person illegally possessing a handgun would be "shamed" by the ownership of a specific weapon if he was not "shamed" by the illegality of owning it to begin with?
There are two answers, and neither makes your case. First, that Holder is attempting to deliberately confuse the rampant illegality in black culture with the lawful possession of firearms. This allows "his people" to continue to refuse to take responsibility for the violence of their inner city culture, and lays the blame at the feet of his political enemies: law abiding citizens who do not belong to that culture, but who coincidentally own guns, and who are blamed (not, coincidentally) as racists for every other problem in that culture.
In other words, whether in 1995 or 2013 or 2050, the excuse is the same: Law-abiding people are to blame for the problems of the black inner city, and it is always somebody else's fault.
The second reason is a much more cynical one. Holder knows perfectly well that this will not solve the problem of inner city violence, but he also knows there are enough stupid people in the country who can be fooled into thinking it will if the lie that the gun is at fault for the evil it facilitates is repeated over and over again. Sandy Hook is a different kind of opportunity, because it involves white children. But it is the same political game as ever: use stupid, primarily emotion driven people to acquire political power in pursuit of a "problem" which politics cannot solve.