Cloudbleed and particularly Cloudflare's response to it (the way they publicly blamed Google) tells you everything you need to know about how trustworthy Cloudflare is. I personally use Google via DNS over TLS, not that it is a good option but I personally prefer that to the alternatives available near me. CenturyLink was intercepting DNS last I checked a few years ago.
If the big players are selling DNS data, I guarantee you there are companies out there approaching every other smaller ISP with a turnkey solution that makes it as easy as possible to do the same thing with some kind of revenue share model.
Not a lot of businesses would turn down extra money like that, when they know their big competitors are doing the same thing.
Unlike most ISPs, privacy and security are a core part of Cloudflare's brand and business model - at least at the moment - so it's in their own interest to actually not do this stuff.
Only time will tell whether or not they pull a "don't don't be evil" on us, but that's a different conversation. :-)