Because you've never seen a real gunslinger in action, just the desp build idiots who only know how to spam one button only.
Don't let Hunk and all the other people who have come and gone destroy the credibility of the Desperado build. It's the closest thing to making a Gunslinger NOT be dead weight in WoE. In certain choke points, this skill is extremely deadly. Used defensively, a gunslinger can take out a capper since they usually tend to wear ED(of course this is assuming they don't get blasted to hell by magic spam first)
/Smh...Gravity gave them 4 possible weapon types to use, and primarily focused on two. Also their HP and SP mod sucks ass

I personally don't play much of gunslinger but the two best slingers I know i've seen with that weapon.
And don't you mean three best slingers?

I specifically remember three.....or is one of them not...nvm.
but why when you can DD pistol?
Or get a vesper optics and card a TG instead.