The Economic Trojan Horse

It seems that most economists now agree that Keynsian policy (i.e., the use of fiscal stimulus to "jump start" the economy) is a load of horse squeeze. To quote the more refined Tyler Cowen, "The science isn't there." Ok, so why is it that everyone I hear from on the subject lately, from Obama to Krugman to the monotone bores at Market Watch, tend to step all over themselves in praise of Keynesian economics, while insisting that all we really need is a big, old-fashioned federal spending program that will "get us going" and "put us back on track..."?