Quod gratis asseritur, gratis negatur.
Translation from Latin: What is asserted gratuitously may be denied gratuitously. Variants: What is asserted without evidence/proof/reason, may/can be dismissed/denied without evidence/proof/reason.
Seems reasonable, right? The crux of the saying is that if you make stuff up without reason, it can simplby be ignored.
It was bad enough when people were making evidence up to support a claim. Now, it seems that people are so lazy that they don't even bother doing that! They just make shit up and the masses nod in agreement. WTF?!?!