Earlier quoted context omitted.
There's a fantastic web series that explains the whole dynamic: the alt-right playbook. https://www.youtube.com/playlist?list=PLJA_jUddXvY7v0VkYRbAN...
It’s reductive to frame this as an alt-right only phenomenon. As long as we’re subject to modern ad-fueled social media, this is the basis for all non-retail politics.
This is a playbook that was utilised by the alt-right first, and adopted by nearly everyone else; particularly (though not exclusively) Republicans in the US, followed by most conservative organizations around the world.