I wonder how much the scientific method went into coming to that conclusion.
Also if anything we are way too exposed to other people's views. Before you could speak to someone random and there was a much higher chance that their opinions were unique because they weren't the next person who binges on r/all. We had many more forums and less recommendation algorithms driving what we consume. Now you overhear people talking about something you just saw the other day online in public all the time.
It is similar to how globalisation is making everywhere feel the same whereas in the past people had completely distinct cultures from one country to the next.