I think this is essentially because the social media and political theatre optimises for and favours popularity rather than truthfulness and scientific evidence seeking. Democracy decides by what people vote - and people don't vote scientifically. If we look at things like prediction markets for instance, we get much better answers for complex issues, because people have skin in the game and loose their money if they're wrong. In current politics, it's ironically more risky and damaging to say an unpopular, uncomfortable but necessary true statement than to simply say a soothing, popular and unnecessary and unproductive lie. After all, lying doesn't cost anything, because society memory of you isn't perfectly logical and unbiquitous.