I am not really sure why so many people here are alarmed at the privacy implications. Google or Apple and your ISP / Telecom already know where you are at all t

I am not really sure why so many people here are alarmed at the privacy implications. Google or Apple and your ISP / Telecom already know where you are at all times unless you are one of the very few people that don't carry a cell phone. Your ISP already knows every site that you look at from your home computer - how exactly is this different? Why is Facebook inherently any more or less trustworthy than any of these other companies? They are just happen to also know where you are when you optionally check in?