We were already living in a post-truth world. Its king just needed crowning. I think it came from the need to go beyond truths. Truths just couldn't convey what we were feeling anymore. They didn't do our feelings justice, and hearing the truth so often made it boring and cliched, so we went beyond it.
Statements that were true like "I'd appreciate it if you could pass me the salt" became "It would be awesome if you could pass me the salt". Volcanoes erupting are awesome. Solar eclipses (although I do think eclipses are happening a bit too much these days) are awesome. Passing salt over the table to pour on one's runny egg is not awesome. If it is awesome to you, then check out a volcano erupting and compare the two.
The truth is boring and cliched because it doesn't change fast enough to keep up with our crazy and sexy lifestyles. It just gets added to slowly over time. The truth is seriously uncool. The truth is a 90's dad in beige Gap Khakis.
So we have to sex truth up in order to make it great again, because the internet made reading and hearing about the truth over and over painfully dull, and humans prefer truth that is playful and very aware of itself. Seeing the truth doesn't mobilise us anymore. Seeing what we'd like to believe is the truth, makes us move. Seeing this self-made truth being crushed will also make us move too.