They're obviously better than the '11 Spurs, but that team was ridiculous record-wise through about three quarters of the season, the '12 Spurs ripped off one of the greatest stretches in league history and the '14 Spurs, as you've detailed, were the great playoff team of all time. Yet not once in that time (nor '13 and it's not as if that Spurs team was too shabby themselves), were they thought to be favorites, let alone overwhelming ones.
Their numbers, though impressive, are due in part to a combination of health and their best players being unable to play virtually unlimited minutes when necessary, two things those Spurs teams have never had in that time. They also have one series win under their belt, their clear cut best player is a PG and they have a rookie coach. There's no historical precedent (that I'm aware of) for this being a championship formula, yet everyone is ready to crown them.
Largely due to a combination of injuries, fatigue and sheer boredom, the Spurs haven't looked like themselves this season, yet instead of being given a well earned mulligan (funny, the Thunder have been) for those things, they've been reduced to being put in the same class as pretenders. Throw out the '12 Mavericks, who had a completely different team and they're by far the most disrespected defending champions in recent memory.