As a counterpoint I have read there are 2 good reasons for these strange and often lengthy demands:
1) To ensure that staff are paying attention: if items are missed or not followed up on and attention to detail is lacking on a list like this, then attention to detail could be lacking in other areas.
2) When touring your whole life is about being on the road, one place to the next to the next to the next, after a while you want any little thing that can help to make a concert venue feel cozy. Remember, they have to go on stage and make the money fans spent worthwhile since touring is where the real money is made. THe bigger the star the bigger the pressure will be and the more you'll want anything at all to keep you in 'the zone' for your performance. Between media, paparazzi, publicists, meetings, phone calls, and hangers-on, as well as a performance to give over and over - I don't blame them. Eminem wants a tub of fish, let him have a tub of fish.