We camp exclusively in Michigan State campgrounds. All of them I've been to have low water pressure at the spigots throughout the campground, a nozzle that doesn't allow for a hose to be attached, and lest anybody try to get creative, a sign making it clear that connecting to a camper is prohibited.
Our strategy is to fill up when we arrive at the campground, and then typically every 2-3 days, I'll fill up our six gallon bucket (standing at one of the aforementioned spigots) and haul that back to the camper, where the bucket has a nozzle that fits right into the holding tank. While I'm filling up the six gallon bucket, which can take a few minutes, I'll step aside if someone has a smaller container or bucket to fill, but it's rarely been an issue.
I just look at it as trying to have good manners