Absolutely a serious question here: what is the big deal with companies e.g. Facebook and Google using your data for profit? These companies provide services that you , a user of their platforms, want. Providing those services is not free, and yet the prevailing sentiment across the internet seems to be, "Wow, I can't believe FB was using my data to sell me ads!"
For one, it pigeonholes your internet experience. Systems like this basically take the simplest, stereotyped, one-note view of you from a snapshot of your online activity, and constantly projects that judgment back at you. Buy a microwave oven on Amazon, for example, and now you're seeing microwaves everywhere. If you browse Youtube with cookies enabled, it's a terribly limited experience compared to with cookies blo…
This is very subjective. You cannot speak for everyone, and meanwhile Youtube generates petabytes of analytics every day showing what people really like, down to each individual.