Move-in fees are pretty common among property owners’ associations and condominiums. Some people call them transfer fees. If your association didn’t charge them a decade ago, then something must have happened during those 10 years that caused them to implement the fee. Try sifting through the HOA documents you received at closing. There should be an amendment in the bylaws or declaration imposing the fee. The seller must not have been very active in the community for him not to know about this.
I get why you would want to get out of your home owner’s association but like anna said you can’t really leave if you don’t sell your house and go. Dues are typically a small price to pay as my experience with home owner’s associations has been pretty good.