Sounds like the 'tender was just hating! IMO, it has become de rigueur to bash New Belgium/Fat Tire (and others) over the last number of years.
That said, New Belgium set the stage with Fat Tire in CO for craft-brewed ambers and was/is a good intro to craft brew for the masses... Now Full Sail out in Oregon is an amazing amber that was introduced a couple years earlier, and was quite popular in the front range too. So perhaps the bartender was implying Fat Tire was riding the coattails of Full Sail. That said, two different (quailty) ambers.
And while I'm on it, I also think solid beers like these, especially Fat Tire are getting some bad juju from people because they have grown and it is not a "hipster" IIIPA, chocolate/mango, hot pepper infused beer from a small pub in Guam that only brews once a year!
It is a solid, quality amber. Is it the best beer ever? I don't think so, but I could drink a bunch of them and not complain.
Hope some of the information (on Full Sail) mixed around my rant might help you!
EDIT: I agree jangelj, Singletrack is good (and around longer) and can be thrown in there too! Fat Tire just got a much bigger/faster following outside the front range in that time period (from my recollections/perception of things when I lived out there during that time).