This phrase used to be used by experts in a field (e.g. law, government, science) after they had spent a huge amount of time (e.g. weeks/months/years) studying and researching every single possible angle on a subject before having the knowledge to say that "
there is no evidence" that a certain statement or object is true.
Nowadays, it is used by
any Tom, Dick or Harry who spent
zero time studying and researching a subject to appear that they know something in depth when they disagree with an expert opinion (the expert opinion has overwhelming proof and is utterly true).
This phrase should not be allowed on any broadcast media unless whoever says it can prove to the world that they have done their research and can prove their point.