They aren't. Next time you're at the store, actually look at what the label says. It'll be a big "CHOCOLATE" and then a smaller "flavored candy".

Fruit juice from concentrate is still 100% fruit juice though. It just had the water removed and re-added.
But they do often make it "cranberry juice cocktail", which is some part cranberry juice and mostly apple juice.

And just this week I saw orange juice that was also part pear and apple juice, but that's probably because of citrus greening killing the orange groves.