In a way, Biden is right. Concerns about his age have been present from the very start. There was a very appropriate time to challenge him on that, or have a more public conversation - before all the primaries were held. Publicly shitting the bed about your own party months before the election is not helpful. Yes, the media environment is unfair, but the party elites don't have to constantly drive it with inside gossip.
It's only the country at stake here and this is your defense? Three things -
One - Biden made it so there was never any primary. Once the incumbent says they are running again, and he was doing a good job, and while some of us were concerned about his polls plus his clear start of decline and the gamble that was, he didn't look too bad. He knew the Dems - they were not going to primary an incumbent and start a civil war - when he looked passable. He used the elitist power of the incumbency to make sure he had no real competition. And, the sick thing is, he did it even when a majority of his party's voters didn't even want him to run. Not the elites. Us peasants. That's arrogance and ego, not caring about the little people, you should be criticizing him for this.
Second - if Biden and his circle had been honest instead of hiding his abilities like traitors, none of this would have happened, but his and their egos thought it would be totally fine to do. So stop blaming people for shitting the bed at a really really big fucking problem that was hidden from them enough to do anything about it. The fact you can still blame anyone but Biden still, it kinda scary.
Third - why the hell should it be ok to put forth a candidate clearly not capable of handling the campaign due to mental dimishment? We are not the Trump party, so don't use him as an excuse. Why are we beholden to this incompetent candidate? This is an entire country on the line, we owe it to Biden? I don't care if his name was Obama, we don't owe that kind of responsibility to any one man. The only thing a responsible party can do is change directions and put someone competent in there. That's called adulting. You know, and for only one of the most important roles in the world - period.