I've heard that sometimes in public health you have to lie to avoid the strange incentives that people acting as a massive group have. But your lies have to at least make sense. When you go around frantically pushing a narrative that is a blatant lie, you lose the public's trust. It doesn't help when half of news programs are brought to you by Pfizer - a company with a vested interest in Ivermectin not working for this purpose.
The randos on YouTube will always be there, but it's the failing of the mainstream media that anyone takes them seriously.