Guess, it has to do with profit margin. To be price competitive and also make a huge profit, sugar is added as a filler. Sugar is cheap compared to other ingredients may be. Added sugar varies by countries.
IMO this is a much more credible take than the prevailing conspiracy theory that Nestle is specifically getting kids addicted to sugar so they'll be reliable Nestle customers in the future. Nestle is like any other corporation- they need to show that profit now. The side effect of getting kids addicted to sugar- which they can also get from Nestle's compeitors- is just a side benefit.
