[scarmig]

The world isn't entitled to knowing whether something I'm alleged to have said or done really happened or not.

For the people who lack imagination: suppose I'm a public official, and a photograph comes out depicting me doing some kind of "dirty" sexual act. Maybe it's real; maybe it's a deepfake; but if confirmed to be real it certainly would do reputational damage. Non-repudiation by definition prevents me from disavowing it, to no social benefit, and it's an anti-feature, in the sense that the large majority of users would prefer to have the ability to repudiate certain message contents than not.

Non-repudiation should be opt-in.