This has been the "cool thing to do" since human beings developed a brain to critically solve problems, like "how do I complete this strike as fast as possible without wasting time?" The solution is to run by the low level enemies that give you no benefit to kill. Hint: The Infinity bounty requires you to get 200 kills on Nightfall- staying back to kill the low level enemies DOES NOT COUNT. You must go to the spawning restricted area. And if you seriously think ignoring enemies that are usually 10-20 levels lower than you is unhelpful, you're the real tool. FYI I've been doing this speed run since the first week, and I may not have been the first but I am sure am proud to be leading the way.