Remove the rear wheel? - they must be referring to the splines on the wheel hub, I only grease that when changing the rear tire, or if I happen to have it apart for some other reason. There is no need to remove the rear wheel to just change the rear end lube. Now if the bike has been sitting for a long time or has not had good maintenance you may want to check the splines for grease, but I have never pulled the wheel off just to grease those splines.