YANBU
Believe it or not, there were cereals packed with sugar in the 60s and 70s when i grew up, as well as crisps, sweets and biscuits!
When we pestered, our parents said no regularly, and that was the end of it.. Sweets were to be bought with pocket money on a Saturday and other sugary products were viewed as treats not regular foods.
Its up to parents to place boundaries, not a nanny state, just as it always has been.
Surely looking after and taking responsibility for your children in every aspect is simply decent parenting..