So do you want to defeat Trump, or do you want to whine about the candidate you have already selected?

I can do two things.

And there's a good argument that a clear-eyed examination of the new information about Joe Biden's current mental condition, rather than simply ignoring it, will help defeat Trump - for some definition of "defeat." If Biden's performance at the debate is reflective of his current mental capabilities, then he can't defeat Trump, and he will be an anchor on downballot Democrats.

So "whining" about the candidate can force him and his inner circle to open the kimono a bit and let people form an accurate assessment of his capabilities today (not two years ago or three and a half years ago or thirty years ago). Which can enable donors and downballot candidates to make better decisions about: i) how to beat Trump in the Presidential election; and ii) how to possibly win the House. Because if Biden can't beat Trump in the Presidential election, the only remaining path to "defeat" Trump is to win the House - which gets ridiculously harder if frontline Democratic house candidates have to defend the choice of Biden as the party nominee.