"And product marketing and placement has absolutely no affect on how one think something taste is good or bad"
Yes it odes.
"My 7 years old nephew hasn't watched a single Coca Cola coke in his life time"
1) It's ridiculous to say a 7 year old 'has never seen an add for coke'.
How would you possibly know that? Unless they are living as the Amish, that kid as seen ads.
2) That someone will prefer one drink over another is not relevant to the argument.
Nobody is making the claim that 'ads make you do stuff'. No Coke ad is going to 'force Pepsi drinkers to like Coke'.
Ads are influential. They root the product in feelings, emotions, those have impact, which is why advertising is there.
3) Your nephew was probably drinking code from some age, maybe as a treat. It was Coke and not some Italian cola, because Coke has such a powerful market position.
In Italy, they drink Brio and it's quite good, you can't even get it here, if you could, people would drink it.
Coke spends billions on ads because they work not because they don't.