OK, so, extend that philosophy to any media content. The method I describe above would force whomever is publishing content that that want to "seem legitimate"

OK, so, extend that philosophy to any media content. The method I describe above would force whomever is publishing content that that want to "seem legitimate" assign a human person (digital signature) as the source. Then, it would be easy to say "well, this content doesn't have a legitimate source that I can point to, so, it's probably fake. And, if people are afraid to post the content without personally backing it up, they probably shouldn't be posting.