You say that as if he has dementia, which he does not. Why can’t we accept that maybe the debate was a “bad day”? Why are we pretending it’s now the norm for how he behaves?
Why are you so sure he doesn't have it? That sure looked consistent with early dementia. And we don't need this to just not be the norm, we need it to be a single solitary event that never happens again. Uncommon bad days are too many bad days. He needs to be "on" too often to trust to chance that he's never going to do this again.
I mean, the Dark Brandon stuff didn’t come out from him sitting behind his desk.
Dark Brandon was a meme coopted by his social media team for in-your-face policy. It had nothing to do with him speaking. And again presidents can just do policy and speeches at their own pace, candidates need to be interactive and ready.
Why are we pretending that Biden is a whole different person than he was even one year ago over this?
You haven't had to have frequent contact with an elderly relative have you? A person that old absolutely can go from sharp as tack to having noticeable cognitive difficulties in a year. That's a long time for an elderly person.