Calvin is still a CP system, so nodes outside of the quorum cannot proceed. The point however is that partitions are rare enough that a CP system can still provide a high level of availability, despite the theoretical limitation. Eric Brewer, who came up with the CAP theorem explicitly makes this point here: https://static.googleusercontent.com/media/research.google.c...
That's an excellent description. And post's author describes that systems behave like CP.
But in general, Google's network is very different than other networks. With their resources they can provide guarantees and capacities other run-of-the-mill data centers can't. So others probably shouldn't listen and assume it applies to them as well.
IME, while Google's network is really good (based on my experience w/ GCP at least), AWS cross-region traffic, for example, is still pretty reliable.
Reliable enough, at least, that trading off perfect resiliency in the face of partitions is worth it to gain strong consistency semantics.
IMO behavior in the face of partitions is a bit of a red herring. The latency tradeoffs required in a geo-replicated CP vs AP system is much more relevant.
