You bolded and took issue to that statement, but is generally true. In a football context, throwing less is generally favorable for the QB. When a QB throws less it's usually because they have more favorable conditions, leading a game, more support from the running game, more favorable down and distance situations, defense forcing turnovers etc. It doesn't require the QB to take as many unnecessary risks, he's not forced as often to make longer, or questionable throws or decisions.
They have different styles and run different type offenses. Brees is in a pass orientated offense and while not generally considered a dink and dunk QB, the Saints offense is more successful when involving their RBs which are usually shorter safer passes. Romo played in a more run focused and downfield passing offense which inherently carries more risk. Romo throwing less passes benefits Romo because of the type passes he was asked to make. Brees stats look better in part because, while a great deep ball passer, because his offense didn't rely on him to have to constantly complete deep passes. His success has come from being able to make the shorter safer passes.
Coaches and fans get enamored by the big arm and/or athletic ability, ala Marino, Elway, or Romo and want to play to those strengths and get tunnel vision by that talent, but that only carries you so far. Romo's offense was designed to take advantage of his strength's, his arm and scrambling ability, but the passing game relied too heavily on that and didn't afford him more shorter and safer throws. Brees was also put in an offense that played to his strengths, but his coaches knew enough to not just rely on that which afforded him greater longevity and success.