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...