This is the bullshit asymmetry principle at work:

The amount of energy needed to refute bullshit is an order of magnitude bigger than to produce it.

a/k/a Brandolino's Law.

https://statmodeling.stat.columbia.edu/2019/01/28/bullshit-a...

The claim is bullshit. We know it's bullshit. Refuting it ties up resources and conversations.

Flag it as bullshit and move on.

See also burden of proof fallacy:

https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFalla...

You don't even have to dispute him. He rarely has any clue of what he talks about, and that's blatantly true here when he believes oil spillings are all about "fish".

Is more about taste than sight