I think you meant to say the 2.7l was 2 seconds faster than the 5.7L?
Anyhow - you're right that an argument isn't worth it. Comparing different platforms with different weights and different gear ratios and #'s..we're not going to get a true comparison of performance capabilities. I really could care less if one truck brand beats another by a few seconds in any sort of drag race or timed event. I care a lot more about how well the average truck performs 100k miles out of warranty.
The bottom line is that the 5.7l has a HP advantage compared to the 2.7l ecoboost and, more importantly for those of us who keep our trucks well past warranty, it has a well-proven track record. I saw someone earlier brag about how there is a 2.7l ecoboost that made it to 400k miles...perhaps a milestone for a F-150, but really nothing to brag about for anything we'd consider a "working" truck. 400k mile Tundra's don't get any special attention because those trucks are simply meeting owner expectations.
The 2.7l ecoboost is an alternative to the 5.0l v8 coyote or 5.7l iForce...I would not consider it to be a replacement for either engine, but that is entirely subjective territory. But however you want to consider it, the average 2.7l ecoboost gets, at most, 4.5mpg better compared to the average 5.7l iForce...statistical outliers and big fish stories won't change that simple fact.