Do they advertise that they have what you want, and then it isn't available when you get there? If you know in advance then what's the problem? All amenities are not available at all campgrounds/RV parks. If you feel they are necessary for you to enjoy your time out, then you need to pick ones that cater to what you desire.
If one were to extend your "logic" then all campground/RV parks should have lots of playgrounds/pools/activities for kids, because many people look for that in the campgrounds they frequent.
"Diff'rent strokes for diff'rent folks."