We can all agree that Adolf Hitler was terrible.

Adolf Hitler believed that 2+2=4

Therefore 2+2=5

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It's disturbing how common this style of reasoning from values to fake facts has become.

Does this fallacy have a name? Should it?

Many on the left can all agree that Trump is terrible.

Trump believes that chloroquine will cure covid-19

Therefore chloroquine will not cure covid-19

@imhinesmi suggests the following:

https://tvtropes.org/pmwiki/pmwiki.php/Main/HitlerAteSugar

A nice way of isolating this fallacy is the following false implicit assumption:

"bad people magically will only associate with things that are bad"