I use UncensoredDNS, which is a much smaller project but also a free DNS service like Mullvad's. And they also shut down all of their unencrypted ports earlier this year.
Here[1] is their reason; "The reason for this radical change is twofold: 1) I want encourage adoption of encrypted and authenticated DNS, and 2) I am sick of fighting UDP amplification attacks."
Here[1] is their reason; "The reason for this radical change is twofold: 1) I want encourage adoption of encrypted and authenticated DNS, and 2) I am sick of fighting UDP amplification attacks."
1. https://blog.uncensoreddns.org/blog/39-the-unfriendly-intern...