What they are saying is supplements are bad for you, get vitamins from food, not pills. It has to do with dose and time, too much VitC too quickly triggers the opposite effect of what you want.

Linus Pauling started the whole supplements craze with hyper dosing vitamin C. Both he and his wife died of cancer. Classic example of Nobel disease where an award causes people to start believing their own bullshit because everyone calls them a genius.