Rooftop windmills

What is it with environmentalists and rooftops? Not content with promoting silly rooftop solar projects I see they are now pushing rooftop windmills which have many of the same drawbacks. The linked article actually points out a lot of the problems with this idea but fails to draw the obvious conclusion.

It appears to me that rooftop windmills are effectively ornamental, like spoilers on ordinary cars. In which case you might as well save money by not actually including any power generation equipment.