Imagine for a moment you're in another world. A rational world.
>Someone says something
>Provides some reasoning, observation, or data
>The others listen as they make their case
"Well gosh, that sounds pretty outlandish but from what I see here there's definitely something going on. Let's check it out."
>They proceed to act in their collective interest and find the answer

Now come back to the real world.
>Someone says something
>Provides some reasoning, observation, or data
>The others may or may not listen
"Yeah whatever schizo."
"That's not possible [because it's outside the Overton window, which has been externally defined]".
"What can I do about it anyway."
"Schizo schizo schizo!"
"Nuh uh!"

See what's been done? Any sense of community or mutual interest has been eroded. Too many have become cowards.