It's post truth, Morgana. If you make something out to sound scientific, people are more likely to believe it's true. In the olden days, we just used to call it lying.
After the referendum, Arron Banks, founder and funder of Vote Leave, said ‘The remain campaign featured fact, fact, fact, fact, fact. It just doesn’t work. You have got to connect with people emotionally. It’s the Trump success.’
Just as with advertising and marketing, these people don't care whether they tell the truth or give the whole picture, so to an extent it has become 'scientific' because it is quite deliberately planned to fool people, using market research and focus groups, etc.
These are politicians who just don't care if they tell the truth, which isn't the same as promising or predicting something which turns out to be undeliverable or wrong.
granta.com/why-were-post-fact/