We had a chance to eat at Tojo's while we were in Vancouver and heard the story from Chef Tojo himself. Very nice dude, and the food was pretty good as well!
One thing I haven't seen mentioned which jumped out to me about the first theory is how would they have inflated the bag with breathable air in the first place? Were air pumps around back then?
For sure, it's much easier to sell any decision if you package it in terms of values and ideals that your population is willing to embrace. It's as true for the US as it is any other country in the world.
Historically the US trade relationship with China was based on a principal that doing so would encourage the adoption of democracy there. Seeing as how that hasn't happened, this kind of rhetoric could just be an attempt to course correct (maybe overly so).
I'm sure the upcoming elections also play a part in this. The article briefly mentions that as well.