To add my bit…… As a devoted dog lover I do agree that there have to be boundaries for dog owners, and one of these is not to allow the pupper into the pool. I see no harm in letting them into the pool area onleash, but not into the pool. I can totally understand why this would upset some people.
Also to wander around the area unleashed is not responsible ownership imo as many people/kids have a phobia of dogs so why make it unpleasant for them. But I see no problem at all with allowing them in on leash.