I have seen this inability to conceptualize what real crowds look like pop up in discussions here on BgBB from time to time, and even ICly in the game. (This bar is empty. Nobody is around. SIC is quiet. etc.)
This is what I picture Red sector being like (minus the umbrellas, because Trash Golems can't afford umbrellas).
Crowd densities like this are why people with swords and sticks can take out people with firearms. There simply isn't much room to create distance. That's not because the street isn't wide enough. There are just too many people in too little space.