The Lawyer is your ultimate authority, and you should be advised by him.
The CCR's are the guidleine, what ever they say.
As to why the HOA would do that:
They probably have a covenant that THEY have to abide, which says that only a certain number of unit may be rentals. If that is the case, then they are between a rock and a hard place because they didn't share this with the residents.
We can't help you; you really, really need a Lawyer.
Good luck and may God bless