It also hasn't been pointed out yet that to compare a coastal city to a landlocked city, you have to go much further out from the city center to capture the same amount of land area.
Massachusetts has a ton of wetlands and salt marshes that can't be built on, as well as plenty of defined park space. Look at the area in this link. I am pretty sure it counts as land, but obviously is completely unbuildable. It's super dense surrounding these marshes. The coast is absolutely littered with them, and the wetlands extend well inland. So if this is affecting density but left out of weighted density, the numbers start to become a lot clearer.
https://www.google.com/maps/place/Ru...!4d-70.9938262