I've lived all along the West Coast from Tijuana to Seattle. There is no place along this coast which I would call homogeneous except the Bay. I would challenge your locals statement, but at this point, I've wasted too much time on No True Scotsman fallacies for this lifetime.

Either way, my community was one of the last diverse communities to get priced out of the Bay (around the early 2010s). Yet, you can find my community in any other populated place along the west coast. The bay definitely has a diversity issue when it comes to interesting people.