We don't completely disagree, I'm just saying that cryptography can help quicker and can solve much of the problem for authenticity where authenticity is can be expected.

And we're talking about a very specific issue here, not simply whether we trust information in general based solely on the medium. Were talking about deep fakes. Whether politician X Y said a specific thing on TV or not. (And not e.g. whether a specific general claim is true or not because that person said it.)

Yes with adequate literacy you can sometimes deduct that you are seeing a deep fake because e.g. Barack Obama or Tom Cruise could have not said it in front of the cameras, but it can be solved with technology and sometimes you will be wrong anyway. (And lets not forget that all of the information you can acquire comes through some media source and in the end you do trust some of them. This includes your teachers. It's just that if you have solid foundations then you are harder to attack. E.g. because no one can go back in time and hack your teachers and school books. But in theory it's still possible. Just think hod dictators do it over the long run.)