Maybe people with likely problems relating to depression see sugary drinks as a good means of relaxing, they taste nice.
I dont have sugary drinks these days, mostly water these days but when I have one its just something orange-ish.
Also, how the fuck can you drink so much soda is just... its like watching an alcoholic down a bottle of vodka, its good in moderation but its shit in quantity.
for me, honestly, i drink that much because of the caffeine... coffee and tea make me feel ill, so i stay away from them.
i felt a ton better when i was drinking nothing but water....