Primitive Society?

Recently, gang activity has been increasing in New York City. Gangs have been an issue in New York for as long as anyone can remember. They have ruled the streets, and there wasn't much anyone could do about it. Not only did ordinary pedestrians fear them, but so did cops. The authority was hesitant towards making any radical moves to stop the gangs, for fear of putting themselves in any possible danger. As a result, gang violence remained intact. However, today, with the very recent rise in the gang activity, the government is contemplating whether they should punish these gang members with capital punishment. Is it fair to give them the death sentence for everything they have done, for the multiple people they have killed, or, by doing so is it making us just like them? By threatening them with capital punishment we are only bringing out the idea of "an eye for an eye". This idea of an eye for an eye was created centuries ago in the time of the Egyptians. People were primitive then, not knowing any better. Are we then being primitive as well? By reinforcing this idea we are showing how society has remained stagnant and is refusing to find alternative ways to fix the issues facing our world today.
The same idea goes for wars. If one nation harms us, and kills our people, are we being any better then they are by going off and attacking them and killing their people? By doing so we are only repeating the cycle, causing it to be endless. Will we ever, as a society, be able to escape this circularity that we have doomed upon ourselves?