I think his point was that dims are clustered together in 6 or 7 spots while the rest are spread out across the country. Perhaps there is an underlying cause as to why the dims all live where they do, or is it that the location creates dims? Don't know.
The perception that the high density of dims in CA & NY would decide the direction of all 50 states is disconcerting. Sure, if there are more dims than others in the US and it was just a popular vote for everything, and we could ensure that only eligible voters voted, then the country starts to have dim policies and leaders.
Oh...you just have to change the constitution. and for that you need state ratifications. Good luck.
We aren't getting rid of the electoral college anytime soon, that's a given.
As to your point about cities, most cities are more purple than pure blue or red. The winner takes all version of the electoral college is the bigger issue, because many people see the pure blue or red outcome and just assume that a city is 99.9% blue where more rural areas are 99.9% red.
Really, instead of getting rid of the electoral college we could add more people to it and turn it into a percentage based voting system much like the house.
California goes 60 dem 40 republican? Then the electoral college would go 33/22.
Then just make the electoral college simple majority.