This author's opinion piece is a good reason why they don't.
We have a woman with a dog, a Border Collie with a proclivity to grab onto the necks of other dogs. The author claims this is absolutely normal and is how Border Collies work sheep. I've only seen a half dozen BC's herd - they were all professionals out on the range working sheep. None of them thought grabbing the jugular was a good way to move sheep. Or maybe they did, but they kept that thought to themselves and just moved the sheep with their eyes and body.
Okay, so maybe this BC is exhibiting totally normal herding behavior. He's not, however, exhibiting appropriate dog park etiquette....and neither is his owner.
Everything is going fine until BC decides to latch onto the throat of a ZOMG! pit bull. The male owner flung the BC off his dog while the female approached the BC's owner explaining/yelling the situation.
Now, if my dog ever bit/nipped/aggressed another dog, I'd be very apologetic. I certainly wouldn't respond with:
“Listen, woman,” I said. “You have a giant pit bull, probably one you adopted from Michael Vick's people, and you think MY dog is going to do a number on yours?”
I'm sorry, what? Here is a woman with a dog-aggressive dog who bites the throats of other dogs and her response is to gripe about the other dog's breed? The dog who didn't "do a number" on her dog? The one who had owners keeping an eye on their dog well enough to be present for the actual "incident"?
It gets better, of course. The author's parting shot is as such:
“I'll be reading about your dog in the papers,” I said. “I'm sure he's got some mauling in him with you as the owner.”
Funny, all things considered. I mean, anyone with half a brain reading this story would probably be a bit hesitant introducing this lady's throat-biter to their own dog. Since the pit bull did not eat her dog or anyone in the park, it seems a bit more likely we'll read about a future dog park incident involving a BC and his throat fetish.
She ends her piece on the high note of her dog ripping off the collar of a Boxer because the dog doesn't like Boxers (seeing a trend, yes?). It seems her dog shares the same prejudices as his owner. Why you would bring this dog to a dog park is beyond me.
PS: For those of you who saw and commented on my now deleted post, thank you. I deleted it because, after some consideration, I did not wish to publicly "feed the troll", so to speak.