I’ve gone through a lot of European destinations where nobody, American or not has, to remove their shoes. And in any case, I would doubt that this was a shoe bomb, especially if there were 4 passengers aboard with false passports.
My suspicion is that the four had smuggled explosives and had actually planned to detonate the plane elsewhere or perhaps fly it elsewhere and take out some other target, but that they just blew up too soon.
I’ve never flown to Asia, so I don’t know their procedures. This is just a comment as a fairly frequent flyer.
I just returned from Amsterdam and was surprised that my shoes were not required to be removed. We did have the body scanner though.