They don't hate magic. It's also stated that they work very well being able to switch between "bow, sword, spell or shield at will and adopting their tactics to the battle at hand." This is given in the guide's description of Redguards. They may work better as warriors, but it also states them working well as mages, or even battlemages at that. The game is designed so you can be anything, so there is no reason why it wouldn't work or make sense. Just because one Redguard from another game didn't like magic, doesn't mean ALL Redguards dislike magic.
Those official guides are written for the game after the game is set. It's nothing about lore. The guide solely describes the gameplay. If Bethesda swap the race bonuses of Dunmer and Redguard, the guide would gladly use the same words but different races as well.
http://www.uesp.net/wiki/Lore:Redguard
The practice of eastern magic, or "Nudri-hi", is greatly frowned upon by Crown and Forebear alike, and outsiders are not tolerated in many parts of Hammerfell.
