It isn't "the more optimized setup". "The more optimized setup" provides absolutely no benefit since the extra DPS is so extremely negligible anyway, and any decent tank will hold aggro regardless. Having some kind of benefit (extra buffer) > having no benefit.
You're essentially saying that the extra DPS is no benefit whatsoever while others are saying that the extra buffer is no benefit whatsoever. Neither case is explicitly true and is largely founded upon personal preference and experience (especially when dealing with your healers). Those of us who prefer to drop Endurance for mainstat are generally those that rarely, if ever, drop into the "buffer zone" when tanking; as such, the buffer is useless because it provides only a marginal psychological advantage that, once you realize it's there, doesn't really have much of an impact as a real advantage. Those of you who prefer to minimize mainstat for Endurance are those that observe the laughably easy state of threat generation in game as well as the low comparative percentage contributed by increasing the tank's DPS (assuming 4 1.9k DPS and 2 750 DPS, a ~50 DPS increase from a high mainstat tank is a ~3.3% increase to total DPS) and conclude that the extra DPS doesn't serve the two primary goals of tanking (keeping aggro and staying alive) whereas the extra Endurance *does*, even if it only provides that benefit in extreme edge cases.
As long as you're maximizing mitigation, neither side is explicitly wrong. It's simply a difference of ideology and personal preference. I'm probably the most vocal proponent of sacrificing Endurance for mainstat but I'm not going to lambast someone because they chose to use high End armorings, or B variant mods, especially if they're a Shadow. I *will* lambast them if they're using those in conjunction with high End enhs and Endurance augs because that's sacrificing enough mitigation to actually reduce your real survivability.