it has nothing to do with taxes. in fact, you will pay occupancy tax on your resort fee.
for the most part, these fees are charged due to the high overhead that resorts have. it takes a lot more staff to run a resort than a traditional hotel. you have additional positions, such as landscapers, pool attendants, etc that are in non-revenue generating roles. for the most part, resorts do try to give you a little value add for these fees, such as wifi, bottled water, sometimes parking. varies by resort.
remember, resorts (and Vegas hotels) will offer deals to get you into the hotel knowing you will spend money in other places. dont assume that since you got a killer deal on a room that everything should be deep discounted as well.
"Cal (9-3) vs. Texas A&M (9-3). On the list of rare sights in Southern California, a team running the option -- as the Aggies like to do with QB Stephen McGee -- ranks right up there with real breasts and 12 inches of snow." Stewart Mandel CNNSI