But how can too much antioxidants ever be bad ?

Antioxidants like vitamin C, E and beta-carotene actively bind to radicals. Antioxidant excess inhibits the useful functions of radicals, like decomposing tumor-cells, and can therefore enhance cancer !!  Radicals also kill mutagenic substances from cigarette smoke. Consuming supplementary ß-carotene therefore inhibits protective action of radicals, increasing lung cancer risk.

Excessive vitamin C can cause cancer by activating mutagenic HCA from food  and can also enhance cancer because tumors need vitamin C to grow.   Vitamin C also increases transformation of harmless iron into pro-oxidative free iron.

To prevent antioxidants from causing damage, you should not take supplements. Simply eat as much fruit as you can, and some fresh raw animal food, to allow the body to absorb sufficient, but not too much antioxidants. Your body can much more effectively regulate absorption of antioxidants from food.

Note : Some people are allergic to specific substances in specific fruits, so increase fruit consumption gradually to make sure you can safely eat those fruits.