The charitable take is that public space is meant to be usable by the general public, not have it adversely possessed as permanent living space. Most "hostile architecture" is designed to prevent only the latter, not the former.
At best, making it impossible for homeless people to sleep at all "solves" homelessness by sending people to an early grave. If that isn't cruel and heartless, I don't know what is.
> The metal spikes, part of a trend called "hostile architecture," appeared recently outside of an office building in Manchester, England, that's managed by commercial property agent GVA, according to The Guardian.
The original wikipedia article uses the following examples:
> - The Seattle Department of Transportation installed bicycle racks to prevent the homeless from camping.[14]
> - A gas station in New Kensington, Pennsylvania installed blue lighting in their bathrooms that make it hard for drug users to find their veins.[15][16]
> - Anti-homeless spikes on London's Curtain Road to prevent homeless people from sleeping there.[17]
The further examples in the wikipedia article are clearly not otherwise unused overpasses.