I think you'll find Mariott are a bit desperate here. August is peak season but Ramadan is offputting to Western tourists as it conjures images of stars and stripes burning religious extremists. Or alternatively a country where all eating, drinking and tourism is banned during the month of religious fasting. Or both. Either way, immediately before Ramadan these hotels cost (at the very least) $150+ per night. On 11th August that cost reduced by a third, for no other reason than Ramadan, which has very effectively deterred westerners from visiting. Remember, this is peak season, at this time these rooms should sell themselves.
The idea that going to the Red Sea Marriotts will acheive anything like an authentic Ramadan is silly, quite the opposite, those I know who have been in the Sharm area during previous Ramadans have found absolutely no difference in their hotel at all, although they have remarked that visits to places such as the pyramids started and ended earlier, but significantly, nothing authentically Ramadan about the big western hotels, or for that matter in Sharm or Naama.
Obviously, reducing rates by 1/3rd has not had the desired effect of filling this empty inventory, so now Marriott is going further, slashing another 25% off the already heftily reduced rooms. These rates represent half the usual August prices but even so, you'll be very unlikely to get an "authentic" Ramadan experience in the Red Sea resorts.
You will however get a half price holiday in peak time...