Lens snobbism is rampant. Many photographers can "make do" with these extreme zooms that are "slow". One that comes to mind is Mark McCall from Lubbock, TX. He routinely uses a Tamron 28 - 200 f/3.8-5.6 to create, in his own words, merit winning images in PPA competitions. He swears by, not at, his Tamron lenses.
It's not what you have, but what you do, with these lenses. Don't knock 'em if you just aren't capable of using them to best effect. It seems others can.
Its not snobbery at all imo, certainly not from me anyway, it's just simply having the right tools for the job and a lens with an aperture of 5.6 would severely limit what shots I could take at times.
It would be fine on a bright day outside but inside a church or dimly lit venue it would be useless.
If I am at ISO 6400 on a 2.8 or even 1.4 lenses to get a decent shutter speed then a 5.6 lenses would be a waste of time and definitely nowhere near an "ultimate set-up"
I completely agree that the photographer has a big part to play in making the shot and its not just down to gear but in a low light situation very few photographers would choose to have a lens with an 5.6 aperture.