Considering most kids this morning will be eating sugary breakfast cereals, I don't see the problem at all.
Shreddies have as much sugar as a scrape of honey on toast and imo are a worse option.
DS doesn't have cereal for breakfast, he always has wholemeal toast, normally with peanut butter (the really good stuff) but occasionally will have honey, jam or choc spread.
I am of the everything in moderation camp too, I don't believe in banning foods, too many times I've seen banning things lead to really fucked up eating later in life.
A friend of mine was never allowed anything sugary at all, ever, and no junk food ever, No sweets, no jam, no honey, no burgers, pizza etc.
As a result when she was 14/15 and started having dinner money, she spent it all on sweets and shit.
She used to be slim, and now is enormous, because she never learnt to regulate her intake of sugar.
My other friends DS, who is 5, is already demonstrating similar, as she wont let him have sweets v often, as soon as he gets them he shoves them in his face like the cookie monster.
My DS on the other hand, knowing he can have sweets/honey/choc spread regularly, will actually leave sugary stuff, as he gets bored of it.