Well... I said "some ISPs" sell your data, not "every ISP", but I wouldn't put it past any of them. Personally, I don't trust cloudflare, I don't like efforts to kill ad-blocking, and I don't like further consolidating people's DNS traffic into the hands of a smaller and smaller number of providers. I've got the feature disabled for now. I wish someone like EFF would set up a DNS server supporting DoT. I'd pay for the service!