""" Thanks to libcontainer, Docker out of the box can now manipulate namespaces, control groups, capabilities, apparmor profiles, network interfaces and firewalling rules – all in a consistent and predictable way, and without depending on LXC or any other userland package. This drastically reduces the number of moving parts, and insulates Docker from the side-effects introduced across versions and distributions of LXC. In fact, libcontainer delivered such a boost to stability that we decided to make it the default. """
In fact it doesn't point out any problems with LXC at all except a general hand-wavy statement about stability (which sounds a lot like NIH-justification).
I was looking for actual problems - since I've never encountered any with LXC/Docker, I'd be interested.
Not because I don't take your argument at face value, but because I'm interested to know what exactly they consider flaky.