Which politicians, exactly? Trump, back during his first term (the rumors about him being on death’s door with COVID were rampant). Biden, for nearly his entire term in office. I remember people insisting Vladimir Putin was on his way out any day now, back in 2023. And there’s an endless parade of rumors about Kim Jung Un keeling over, Ayatollah Khomanie being on the way out, ffs “Castro is dying, get in the boats!” was a thing people said about Fidel from his mid-fifties until he handed over office to his brother Raul in 2008. Pretty much anyone the US government / media doesn’t like gets a scattershot “dude could die any day now” headline from time to time. And the more reactionary the source, the more credulous the allegations.

But Trump was showing early signs of dementia during his first term. He’s showing signs of rapidly-advancing dementia now. Non-dementia health claims about other politicians without evidence in no way discredit the claim that he’s visibly declining with dementia symptoms. The difference here is evidence. (And is it really an improbable that an elderly President would suffer dementia in his second term, and that his staff would try to cover it up?)