If you criticize Biden's obvious mental decline, you are being ageist and ableist.
You're also being racist and sexist because it's clear that you don't trust Kamala Harris to take over.
I don't agree with the latter. I believe that people don't want Harris because they think she doesn't have a chance against Trump.
Biden has given too little exposure to Harris, and the Democrats have failed to identify a credible substitute for Biden. Now it's too late.