I honestly don't know why anyone (the one sending or receiving this type of text) would take offense...

In the text, it sounds like a neighbors dog isn't just being walked off the leash by owner, but out "wandering" alone and on someone's property. The fact the guilty party(dog owner) is being politely notified is a gracious reaction compared to simply calling AC and requesting pick up of a dog with no owner/leash wandering the neighborhood.

I can assure you this much, if any of us were the dog owners and the offended neighbor in this scenario just called AC without even trying to contact, every single one of us would be upset with the neighbor for not even attempting to notify.

I get how we can break the text down and suggest "well the neighbor could of just talked to us" or "the neighbor is wrong/dumb for citing ordinance/laws" or providing reasons like grandkids, grass etc. But even all of the things included in the text would be far more favorable, to 100% of us, rather than the neighbor providing no notification and straight calling AC(an option the neighbor had perfect legal right to do).