Why is it a fight at all? I enjoyed the paper for a few insights into the implementation of containers, but I didn't find the performance comparisons very relevant. As another commenter noted: it's not surprising that namespaces and cgroups are a crapload less demanding than a full virutalization stack.

I don't much like referring to containers as a virtualization technology, although it seems like that fight is lost. In my view they aren't the same thing, they aren't solving the same problems, so seeing people line up defensively around one or the other is sort of amusing.