Every community, every Home Owner's Association, every spot in the USA has some kind of zoning rules. Each one is different. Even in the same neighborhood, it's possible to have different rules for homes that are right beside each other. It just depends on where the zoning lines are drawn.
If I were you, I'd dig into the original paper work you signed when you moved into the community and see exactly what it does say about parking RVs, cars, trucks, and trailers at your residence. If nothing is stated, than you have every right to challenge this decision. Demand from the new manager to see the written code where it's stated. If he can't produce it, he's just being a bully. If he can produce the associated rules and by-laws of the community, then kindly thank him and then you'll just have to oblige to the rules.