>As a consequence we digest fruits differently compared with processed sugar, as the absorption of fructose when eating fruits is slowed down.
When sugar is introduced to the body the liver begins to store/process the sugar. So it doesn't matter whether the sugar is from say coke (high fructose corn syrup) or an Apple.
What happens when the liver can't store/process the amount of sugar you ingest is the body triggers insulin production, and while insulin production will be linked to obesity the insulin itself is the real harm to the body. Insulin triggers the bodies production of fat cells to store the sugars it can't process. Also, Insulin has the effect of enlarging the bodies cells (fat cells, cancer cells, etc...) this can lead to enlarged organs (liver disease, heart disease, etc...).
There is something to be said that an Apple has nutritional value that the soda is lacking (plus fiber), and this can account for some people drinking multiple sodas a day (maybe even a 2 litter) but very unlikely to be eating 12 Apples a day; nevertheless, the underlying sugar is harmful vis-a-vis insulin spikes. The real difference is the person eating the apple instead of drinking the coke is likely to stop their sugar intake at 1 Apple and is more likely to incorporate some form of exercise. Personally, I go by a rule of thumb I try not to consume anything with more than 10g of sugar (a whole apple is almost double).
>And our taste buds love sugar because our bodies crave for fruits, to fuel our big brains. We would have never developed this trait if naturally occurring sugar would harm us.
Humans develop traits and cravings for things that have detrimental side-effects quite regularly. It used to be that Type 2 diabetes was called adult onset diabetes, in fact in the UK kids weren't diagnosed with Type 2 until the 2000's. Despite hundreds of billions a year spent managing Type 2, in most cases it can be completely prevented and even controlled to the point people can stop taking any medication through proper diet.