Not sure that's correct - in Old English "dive" was a weak verb. It has sort of bucked the general trend in becoming strong - mostly an American English evolution."Whinge" is a well-known British term for incessant complaining.
Oh - yes, agreed on the 6/6+ ranking. Who knows what the HTC is made of, or designed to withstand, so it's just an isolated data point, but with regard to the iPhones it suggests that Apple made more effort to strengthen the 6+ than the 6+.
I'm also impressed that they followed up. What will be interesting now is whether any significant reports of bending in pockets (the original alleged concern) actually surface, since it's not really relevant if the only way to break them is deliberately. Given the measured required forces for all these types of phone, including the weakest (HTC), it would seem that even if it were possible to exert that much force within a pants pocket, serious discomfort, if not actual...
That's not going to be the failure point in that bending mode. The axis in question is parallel to the back plate, so that plate provides very little rigidity. The resistance to that bending mode is provided by the structural components orthogonal to the axis - the sides of the phone and the internal reinforcing struts.
Polymer composites have come a long way in terms of strength-to-weight ratio, and it's no surprise that a plastic phone can perform well in these tests. The design choice of aluminum is unlikely to be based on strength at all these days - more on the aesthetics of the device - and the trick is making Al structures strong enough.
I doubt that they adjusted, because the increased moment due to the length is real - in terms of how it affects load to failure. The reduced load to failure, relative to the 5, is not entirely explained by the increased length though- the remainder is probably just the design change in device thickness, material thickness etc.. The 6+ having higher load to failure than the 6 is curious in that context.