(1) You cannot expect to use/carry a 5.5" iPhone 6+ the same way you used/carried your 4.0" iPhone 5.
(2) The force one's pocket exerts on a phone would not be enough to cause it to bend.
(3) There are literally millions of these things out there. How many CONFIRMED instances of bending have been reported? I know people won't believe Apple's 9, but I have yet to see any alternative number being thrown out there.
(4) I put my 6+ in my pocket, but DO take it out far more often than I did my 5S....not because I'm afraid of it bending, but because its BIG and uncomfortable. I knew this when I bought the device. I was aware that it is considerably BIGGER than any device I had previously owned. I knew my use case would change due to the change in size. I made all these decisions before buying the device. It amazes me that people don't think about their purchases more.
You are correct - people have been putting mobile devices in their pockets for quite some time. Those mobile devices also haven't had 5.5"+ displays.
Use your brain. You can't treat the device the same way. Because its not the same device. Just because something FITS in your pocket, doesn't mean that's where it should go.
I know it is hard to believe in your apple centric world, but 5.5 screens have existed for a while on other devices. Shocking.