If they'd told you at the start that the ticket was $1820 incl seat selection, would you have an issue?
Its more the psychological aspect of being charged an extra fee, which I get, maybe a better way is to do what the cruise lines do. you can either book a specific seat for 1 price, or book a "guaranteed seat" for a lesser price, but you have to put up with completely random seat selection. Same net effect but different way to sell it. They effectively do it now with seat only, set and bag or the works, why not have seat specific pricing