If public hospitals suddenly decided to turn away emergency room patients who don't have coverage, I would absolutely criticize them. Emergency rooms are not expected to directly address the lack of health coverage, but it's within their power to mitigate one of the most painful and horrific consequences.
The same goes for city planners. As a taxpayer, I do not want to pay for benches designed to be hostile to the homeless. If you already have it so bad you need to sleep in the park, I should not be spending money to make things more miserable for you.
Public park designers, and even municipal clerks who actually order benches and suchlike, do not do anything similar.
For the same reasons the EMTALA passed, we should be killing sit/lie bills - and hostile designs like this - whenever we see them. Park benches are about the absolute lowest form of safety net you can imagine for a night's sleep, just as ER treatment without asking questions is for health. It's so far below the bare minimum that it would be repugnant to deny it.
A bigger problem I see is that such a bench is hard to position on a curb, next to a wall, etc, where both sides cannot be made accessible.
http://cyan-teak-furniture.com/acatalog/garden_bench_gift_id...
The former is unpleasant to see, but not actively hurting you, the latter case scream clear malicious intent.
It's like criticizing people for having locks on their doors. It would be great if people didn't need them. Unfortunately, certain "societal shortcomings" make them a necessary risk-mitigating measure.
I, for one, very much like the design of the Camden bench. It's so less obtrusive and aggressive than e.g. spikes on a storefront. It's much harder to accidentally get hurt by it. These things, which are actually hazardous, not merely preventing unwanted usage, are "unpleasant design" to my eyes.