It isn't even that the evidence is ambiguous -- as is so often the case in public policy. I will freely concede that while I am reasonably confident that the broadband stimulus package is a good thing, I can't prove it, and the data will probably remain rather murky for some time on whether it accelerated deployment and to what impact for the economy as a whole. This is why I enjoy good debates with my opposite numbers who actually come armed with relevant data. A lot of times in our messy world, policy boils down to best guesses and trade offs and we need to remain open to new data and willing to acknowledge when a policy need correction.
But this is a classic case of no data driving policy, because the people pushing it want to believe.
Happily, as businesses become increasingly invested in social networking and it goes mainstream, this idiocy campaign is rapidly losing steam.