"Keynesianism has conquered the hearts and minds of politicians and ordinary people alike because it provides a theoretical justification for irresponsible behaviour. Medical science has established that one or two glasses of wine per day are good for your long-term health, but no doctor would recommend a recovering alcoholic to follow this prescription. Unfortunately, Keynesian economists do exactly this. They tell politicians, who are addicted to spending our money, that government expenditures are good. ... In medicine, such behaviour would get you expelled from the medical profession; in economics, it gives you a job in Washington." (quoted from here)
I agree, although I would replace "a theoretical justification" with "an alluring justification"