Because the people who support such behavior do this themselves to get attention online with all their crazy theories. I know lot of these people, they are depressed, isolated, and irrelevant, so they do the only thing they know how to do. They act outraged so they can be a hero and give purpose to their lives. And any story or meme that does the same, they naturally glom into it because it gives them fodder and and validates them. And the people I know are smart.

Human's vast intelligence is eclipsed by one thing: Our capacity for delusion when it serves to put ourselves at the center of attention and power.