No one is demonizing this particular thing. People are complaining about a senator who needs to give way to a younger, more progressive person.
Like a 70 year old. /s Jokes aside this highlights things well.
Seriously though, no one is demonizing the thing. They're pointing out the thing adds strong evidence to the arguments they've been making for the better part of the last 20 years. When W Bush went under the knife he signed over power to Cheney. That's the responsible thing to do. On the same token, Feinstein has indicated the likelihood that she is unable to serve her role in numerous ways, with this just being one more way. If she can no longer speak for herself, how can she speak for Californians? I live here, BTW. I'm affected directly.