There are many countries where ISPs are obliged by law to spy on users, and retain logs for many years. DNS manipulation also used as a cheap censorship mechanism. So Cloudflare easily can be a better option for hundreds of millions if not billions of people. As a rule, local actors present way more serious threat compared to US agencies for majority of the planet's population. That said, Mozilla, of course, must be very transparent with such big changes, and explain them to users not using just "more secure" wording.
You are refuting the statement I never made. There's no such thing as general threat. So who's data? If you are Julian Assange you should be afraid of US spying agencies, but if you are an Uzbekistani dissident it's your gov't repressive machine you should care about, and tracking possibilities of your direct adversary will be diminished with the discussed Mozilla's move. If you are an average Joe in a small town you may find it safer to trust faraway commercial entity rather then your neighbor's nephew who works in a local ISP.
