IIRC estate agent (realtor) fees in the UK and most other countries are in the range of 1-2%. Here they are generally 6%, and as others said, sometimes you get great advice and service, and sometimes not so much. It's a racket, frankly. Luckily all that margin is drawing competition and lower cost alternatives are penetrating the market.
Figuring a fair value, advertising/marketing, closing a sale, and processing the transaction are useful services. But they don't need to be compensated at maybe $500 per hour. Selling your house isn't rocket science. I sold my first home years ago, and it cost me about $750 in legal fees which was about 1%.