I don't know but agree seems cruel. I know one of our residents south of Tyvola has a baby deer living in her rear fenced lawn. The mother had two babies a few months ago. She would come every evening and nurse the babies. The last time I checked a couple of weeks ago the resident told me the mother deer and one young baby deer left together. 'The second deer has remained in her rear yard and she tells me it comes running every time she goes out the door. I know her immediate neigbor is one of those Nut Cases that would possibly put down poison or worse.
I would suggest you speak to animal control through 311. They would be able to confirm if barb wire is safe allowed, or not.
Cerainly not friendly regardless if it breaks any ordinances that city has on the books.
I will check myself with zoning to see if there is any violations per zoning and post a response just for general information.
I don't know who the neighbor that put the barb wire up so this will not be directed at them by me. It is a good question and a great point by you.
My yard is welcomed to all critters also. They have to eat and P&R and Greenway didn't seem to care about the critters in the woods prior to creating more green space. We encrouched on them!