The tactic itself involves utilizing quick reflexes to spot an enemy, center them on screen as best as possible, and then zoom into your scope only to then fire as soon as the crosshairs are visible.
Some view it as an exploit. This is due to the fact that the crosshairs essentially "lock on" briefly and allow one to achieve relatively easy one-shot kills. A missed shot usually means one need only quickly repeat. Since it's primarily dependent upon reflexes and simple visual cues, sufficient practice by any player eventually leads to the ability to quick scope repeatedly with a diminishing overall vulnerability while doing so.
The tactic is helpful for snipers while they're on the run, in close quarters, in place of a weaker secondary weapon. However, abuse of the tactic as a primary method of fighting has lead many to view it as the "cheap" preference of noobs. Many who rely on quick scoping have furthered this stereotype by abusing it repeatedly, even going as far as ridiculing those who snipe in more traditional fashions (often calling them "hard scopers" in a derogatory manner).
They often think they are 'more skilled' than all the other players, and are quite full of themselves.
Most Call of duty Quickscopers only use the sniper rifle for this tactic because they think they are famous over youtube, or that being an on a youtube channel with a number next to their name makes them notorious. Other fps gamers do this technique for fun or when they are under pressure i.e Clutching a game while using a sniper rifle the old traditional way. They do not overuse it they do not boast about them being better than others when doing it, they just play like any other normal gamer.
Quickscoping should not be an excuse for gamers to think they are better and more skilled than other players just because they have a new style of sniping.
Gamer 1: Hey man did you see that kids final killcam he quickscoped me.
Gamer 2: yeah he and his friends have been doing them non-stop, I think they are overrated.