I have a big problem with that statement. It doesn't matter how long, 100 yards or 100 miles, the race is, aero is still aero. It's simple physics. Lower drag = higher speed for a given power. There is no less reason to be an a super aero setup during a sprint than there is during an Ironman. You will still have the same reduction of drag.

Now what they may have been trying to get at, but in the wrong manner, is that if the course is EXTREMELY technical or your tt bike handling skills are not up to par, cornering could be slower when riding your tt bike. Typically sprint courses will have more turns per mile than an Ironman, which often include extremely long straights or sections with no turns.

ETA: Looks like Cody beat me to it.