It's people getting in each other's way, not the smell and not the danger.
In the same way you can play loud music at 3 am in the middle of nowhere--but not around other people who want to get some sleep.
The more people around, the more conflicts will arise.
A compromise needs be assessed between the extra benefits of greater population density vs. the detriments of greater population density.
On the one extreme, you are all by yourself on a desert island and totally free of the will of others.
At the other extreme, living in a crowded lifeboat with next to no individual freedom.
Somewhere in the middle is the happy medium.