The author seems to think Mozilla should have protected our privacy by having someone act as the proxy for the request.
On the proxy part, they actually already have that and using it for some other parts:
https://support.mozilla.org/en-US/kb/ohttp-explained
TL;DR: Imagine an HTTPS-over-HTTPS proxy. Try to explain it like something groundbreaking without referencing existing tech. Now you have OHTTP.
https://firefox-source-docs.mozilla.org/browser/components/mozcachedohttp/docs/index.html
https://www.fastly.com/blog/firefox-fastly-take-another-step-toward-security-upgrade
It makes me scratch my head a bit why I've never see it enabled for DNS-over-HTTP in default stock Firefox config despite it being supported for years - the endpoints are just not configured. You have to know about it and configure the barely documented URL in about:config for that. Unlike for newtabpage and the FF shopping feature where OHTTP is used by default. Infra costs?