Wouldn't a talk with the park owner be more productive, one in which you suggest that the park owner have poop bags and disposal bins around their park at handy intervals, along with notices for pet owners to clean up after their dogs?
Really, it isn't as if someone preaching to the rest of us is going to have any impact, as it is unlikely that the culprit is reading, and I happen to clean up after my dogs.
This original post would be like me going into the other sub forums and reminding people to clean up their campsites before they leave, or to not transport firewood, or not to put bottles in the fire pits, or not to throw garbage in an outhouse. In other words, it's pretty insulting.