I don't know that the hash preferences in the public key are relevant to the issue talked about in the linked email thread. Currently GPG (and Sequoia) will rej

I don't know that the hash preferences in the public key are relevant to the issue talked about in the linked email thread. Currently GPG (and Sequoia) will reject the signing of keys using SHA1 if they claim to be recent. The preferences would allow you to send me two messages that used the same SHA1 hash for the signature. I would never know that it had happened as I would never see the hash, only the valid signature. Both signatures would be logically valid as they came from your assertive action.