Why cities are full of uncomfortable benches

Defensive Design and Hostile architecture

They are meant to change behaviors (e.g., reduce loitering, prevent skateboarding). However, it doesn't address fundamental problems of homelessness, which has increased in New York City due to lack of homeless shelters.

It raises important questions about who the public structures are serving.

Shouldn't cities put more homeless shelters (which costs more money, but definitely more effective) than installing uncomfortable benches and even leaning bars (which only improves the appearance only)?