I saw an interview on Bloomberg TV with both the Unbox Therapy and Consumer Reports guys. Consumer Reports admitted that they did not specifically apply pressure to the part of the phone that that Unbox Therapy did. There are titanium reinforcements in the phone, but they end near where the volume buttons are. That is why the Unbox Therapy guy was able to do what he did without much force, while Consumer Reports found it to be much more difficult. CR was pressing against titanium, and UT against aluminum.
So, if you apply pressure to the right (wrong) part of the phone, on purpose or accident, it will snap like a twig. That's just reality. Deal with it.
That said: if you are more interested in using your 6 Plus than in bending it, buy a rigid case. Problem solved.