In a blog post on ungleich.ch you can read why you should stay away from DoH, DNS over HTTPS, now being rolled out by both Google in their Chrome browser and by Mozilla in their Firefox browser.
DoH means that Firefox will concentrate all DNS traffic on Cloudflare, and they send traffic from all their users to one entity. So what does that mean? It means people outside the US can now be fully tracked by US government: now some of you might wonder if this is actually in line with GDPR (The EU General Data Protection Regulation). It is indeed very questionable if DoH is rolled out as default, since users do NOT opt in, but have to opt out.Quote from the blog post on ungleich
The author asks if DoH is bad only for EU citizens.
No, it’s bad for the US citizens too. Because whether you trust Cloudflare or not, you’ll end up directly supporting centralisation by using DoH in Firefox. Centralisation makes us depend on one big player, which results in fewer choices and less innovation. Centralisation affects everybody by creating a dangerous power and resource imbalance between the center and the rest.
Have you deactivated DoH in your Firefox browser yet?