He didn't say "Python doesn't work well for IP stacks" (although: for special-purpose userspace IP stacks, people have done it). He said "Python only works for single-user human-speed use cases". Which, obviously, ignores the fact that every 3rd west coast SaaS tech company has Python at the core of their stack.
Could you elaborate? Are you talking about e.g. numpy and scipy? Python is good at calling C libraries but that doesn't make it good for writing an IP stack or a device driver or an OS. Are you arguing against the "single-user" point or the "human speed" point?