Hmm this article seems misleading. I suppose it's trying to make the point that application designers usually don't need to think too hard about it, because it's already being addressed by a quorum consensus protocol implemented by someone else. This is a bit of a tautology though; the author seems to be saying 'assume you have a solution to CAP theorem -- now isn't it silly to worry about CAP theorem?'.
One of the fundamental assumptions of CAP theorem is that you can't tell whether or not you have a partition. If you have an oracle that can instantaneously tell you the state of every subsystem, then yeah, CAP is pointless.
But if one of your DBs is connected, reporting itself as alive, and throwing all its writes into /dev/null, you won't be able to route traffic to a quorum of healthy instances because it's not possible to be certain that they're all healthy.
This is what CAP theorem is about: managing data in a distributed system where the status of any given system is fundamentally unknowable because of the Two Generals' Problem (https://en.wikipedia.org/wiki/Two_Generals'_Problem)
In many cases in Cloud though, we can skip that technical stuff and design systems as if we really _did_ have an oracle that could instantaneously and perfectly tell us the state of the system, and things will typically work fine.
I think that's a brand new sentence