They didn’t ignore they backlash, they promised to “always” have split screen going forward.. Only to not even make that promise last a single game. Infinite didn’t even have network coop at launch. At this point no one should trust anything 343 says. Their track record speaks for itself.
RAID is redundancy. It saves your data if a or two drive fail, but does not help you if the entire RAID system dies (power surge, fire, water damage). Generally if it is on the same system it is not a backup.