Go to any WWE show and listen to the crowd when John Cena is in the ring. Typically you'll hear a 50/50 split between "Cena Sucks!" and "Let's go Cena!" When you listen to the "Cena Sucks" part closely, you can hear the voices of 30-somethings who are angry about Cena for the 1000th time in the last decade. When you listen closely to the "Let's go Cena" part, you can hear the voices of pre-teen wrestling fans and their moms.
Considering Cena's fans are typically quite young (it's likely because of all the work he does with Make-A-Wish and other charities), it makes plenty of sense to always start Raw with the Doctor of Thuganomics (does he still go by that?).