Then its regular sugar addiction and not necessarily related only to milk tea.
Milk tea does not need to contain sugar. Bubble tea chains usually give you the option to choose. Also when I visit indian friends some of them usually refrain from putting a lot of sugar into it, not bubble teavin this case but still milk tea.
and sugar - lots of it. Needs a control group that consumes equivalent quantities of sweet caffeinated soda.
Black tea contains caffeine, so yeah.
There are people who drink that much Diet Coke each day. I wonder if it's the same type of thing?