The city shouldn't do things that the people who live in it disprove of. If you can find me a majority of local people who agree with this then I'll buy this answer. This is a bit different then most other situations though. This is genuinely effective activism that will improve the quality of some people's lives. I don't see what's wrong with this especially if no one is harmed and no one's private property rights have been encroched. From what I understand this was done on public property that was "unattended" until the law was changed to exclude this practice.
From this statement:
Since the city changed its [unattended property] ordinance, barring me from putting them on public land, I can only go with private land
I also see no valid reason to allow the government to damage property that is confiscated without paying them back. That's insane in it's own right.