One must remember that the Android Kernel is a fork of the mainline Linux kernel that Ubuntu has been using since 2004 and has been around since 1991.
The best source for Android kernels with proprietary blobs or binary drivers for specific target devices is CyanogenMod as those devs have extracted the kernel for people to build from source.
Of course, when an Ubuntu Touch device goes into development for commercial sale, the manufacturer would take the Linux Kernel, tweak and add necessary drivers to deliver maximum performance on the hardware as is currently done with Android devices.
So if anyone wants to accuse Canonical/Ubuntu of "stealing" any part of Android or CyanogenMod, ask where the kernel came from.