[motohagiography]

There are DRM and signing schemes, stegonography, etc, but in the moment, people don't care. Or rather, the message registers in their minds whether it happens to be true or not. It's how advertising works. Beliefs are essentially tribal, and we all believe our tribal sources. If a source of news isn't a part of your tribe, you're probably not going to believe what it's saying until someone from your ingroup verifies it. Crypto doesn't do that.

The irony is that we all trust crypto because of the perceived tribal affiliation of the developers as well, which doubly reduces the case for crypto verifying media.