iPhone 6 Plus Touch Screen Failure Due to Sweat Used Just Like iPhone 4

Is the iPhone 6 Plus super sensitive to water and sweat on the surface of the phone? I just had mine die, from what I thought was normal use since I subjected my iPhone 4 to the same level of use for years. I would tuck in in the side or back of my gym shorts while I road my bike trainer or worked out. It got a little sweaty and I would wipe it dry. Is this an issue with the design or a manufacturing defect? Or just a device that is not as good and robust as the iPhone 4?

I am very disappointed in Apple. I would expect they would make a better product or one with at least the same level of durability. Or was this phone just a manufacturing defect? The Apple Store here in Shenzhen China made me pay for a replacement since they say it is water damage. I never dropped it in any water, it just got a little sweaty on the outside. I remember getting my iPhone 4 very wet with rain and never a problem. I don't think you can do this with the iPhone 6+.