It is to do with the quantity of fruit you can consume when baked due to the amount it reduces. For example, you can eat a lot of apples when cooked and the body does not realise how much food it has had in relation to if you ate that fruit raw.
Same goes for blending fruit in a puree or smoothie, you can consume greater amounts than if you were to eat it raw.
However.......If I bake one banana then I don't syn it because I would eat that one banana raw!