Let me get it straight. You want to be able to engage with a commercial entity, but you don't want that commercial entity to be able to look at anything that results from you interacting with them? That doesn't even sound like a good user experience. I want the companies I engage in business with to be able to look at the data within the confines of our relationship and be able to do useful things with it.
If you don't want Google to be able to do anything at all with information you put into their system, easy, don't open an account!
I can agree with some of the other points, Google shouldn't be hoovering up mountains of data, etc. Just have to be careful of extremes. If you enshrine something bad in something as difficult to change as a constitution, you're stuck with it, and all your unintended consequences, potentially forever. You say "you can't actually enforce this totally in practice" but have you ever met a law firm? They would absolutely take the most extreme possible interpretation and milk all of society for billions a year if they can find an appropriate avenue.
This kind of extremism is what derailed some constitutional reforms in South America over the past decade. It started with reasonable center-left people saying some reasonable things, the radical left seized the process and wrote the final draft and faced with a choice between insanity and an unsatisfactory status quo people made the only palatable choice.