If you pick up a bag of apples and find one bad, do you take that particular bag home? Probably not. You would be reasonable for avoiding the bags touching tha

If you pick up a bag of apples and find one bad, do you take that particular bag home? Probably not. You would be reasonable for avoiding the bags touching that one, just to avoid the rot. The reason "on bad apple spoils the bushel" exists is because obvious rot generally means there is other rot you cannot see without further inquiry - and that those without rot will probably be tainted soon. And that's the problem: Once you find one bad speaker, you have to be suspicious of so many more. It is probably better to move onto something more trustworthy because watching nonsense means you've increased your chances of remembering and repeating nonsense later.