The Media Doesn't Call Races: State and Federal Officials Do
"We have now sunk to a depth at which the restatement of the obvious is the first duty of intelligent men," George Orwell
The media does not pick the winners of presidential elections. Contrary to an infamous New York Times tweet, it has zero role in any elections. The media, on its own initiative, handicaps races, predicts winners, and makes assorted claims about the process or the outcome.
This does not mean that it is an authoritative source or that anyone is obligated to listen to it, let alone that any political candidate is obligated to concede anything.
Elections are a process that conclude with a certification by local officials, by the Electoral College process, and by Congress.
Most of the time there are clear results and all of this becomes a formality. As a result a lot of people have confused media predictions and calculations with outcomes.
However when an election is disputed, as it is now, then the process must be followed.
Biden's claims of victory are inappropriate. If they were inappropriate before the media's predictions, they're just as inappropriate now.
To argue otherwise is to argue that the media, rather than our officials, determine winners in elections. And that's a dangerous level of constitutional illiteracy bordering on a media coup.