I don't think anyone believes CF will start selling data, that's not what the article argues.
Regardless, it's opt-out not opt-in. Which is against newer consumer protection laws such as GDPR.
> DoH is vital to protect users around the world from censorship and worse.
This isn't black and white. Yes there is upside (as both you and the article agree), but the downside of how DoH is implemented here is that you have to point all your DNS queries to a US company. Historically we've seen how this is a bad idea for global internet privacy (eg. PRISM, etc).