Any company in the Bay Area that isn't tiny definitely has somebody on board who knows what a polycule is :)
It is usual for a large number of companies (and tech folks) to know what that means, but disproportionately so for the Bay area. The blog poster certainly works for a company I'd call Bay adjacent, so they wrote in a language familiar to them.
It has nothing to do with "only place that matters", but simply explaining that given the context of the writer, it's a high likelihood they assume general familiarity.