You're probably going to get attacked for saying this, but I agree with you. Many RV parks are being turned into trailer parks. And I'm not saying everybody who lives in a trailer park is bad, but they do tend to attract an undesirable element at times. Many of the RV parks put these park models in and just rent them by the day and that is not too bad. You still have an RV park then. But when they start renting them long term as well as have long term RV rentals, they can start to get junky if the management doesn't keep up with it.
Personally, if I owned an RV park, I'd probably allow long term renters as long as they were the full timer RV type of people, but I wouldn't allow people to build things around their RV. No decks and things of that nature.