It's supremely arrogant to tell your users to change the kernel they are using because you couldn't be bothered to fix a regression in your code. The problem with that approach is self-evident.
Well I guess their argument is they cannot provide secure sandboxing without this feature, and they do not want to ship it with weaker security.
I'm not sure I would say its supremely arrogant to tell them to upgrade their kernels. I'm sure if they realized that they were breaking sub 3.16 kernels they would of announced it before hand, but they fudged that. So instead of fixing it to not use a kernel feature they wanted to use, they just said "well this sucks"