In part, the article quotes Eugene Morton, a zoologist and animal communication expert at the National Zoo, [I'm not sure which zoo that is]:
“Barks are used by juvenile wolves, by pups. It’s neotenic — something derived from a juvenile stage, and kept in adults. That’s probably what we selected for,” said Morton. “We don’t want dogs who are dominant over us. The bark might go along with that breeding for juvenile behavior. Or it could have come with something else we selected, such as a lack of aggression.”That reminds me of an amusing idea I once heard, that dogs are wolves that never really grow up, and we like playing with them, because we are apes that also never grow up! Whenever Penny and I are running around the house playing keepings-off with a soft toy, I think of it, lol.