The lake is part of the commonly owned parts of the community.  You're renting the separate, individually-owned part of the community that belongs just to the landlord.  You don't have a lease with the whole community, so this restriction is probably legal.  If the apartment was advertised to you for rental, as including the lake privileges, you might be able to go back to your landlord for false advertising and maybe get a rent reduction.I doubt that the lawsuit excuse makes a whole lot of sense, but I'm not sure it's even necessary.