"Canonical has put its users over the barrel"

This seems undeservingly harsh. They have an opt-out system and that's "over the barrel"? If so, then if they were to hypothetically sell a users' list of most popular apps they ran or something like that, what would they be doing to the user and how would the barrel be used?

Privacy is a serious question for businesses, and "you can opt out" isn't a serious answer. It is a serious question for everyone and you provided no explanation other than your opinion as to why "you can opt out" isn't a "serious answer"