A different line of arguing may be helpful: not even GnuPG validates DNSSEC signatures (source: https://dev.gnupg.org/T4618 ). That's why DNS key discovery schemes are not enabled by default there (WKD is).
But it’s certainly easy enough for GnuPG to check the DNS flags to verify the resolver has validated the DNSSEC signatures, therefore authenticating the openpgp record for its use, which is the point.
This is how DANE records work; SSH doesn’t validate DNSSEC signatures either but that doesn’t stop it from using SSHFP records in the DNS when they’ve been signed.