If your fine with groupthink, personality driven research and science as a priesthood, then sure, why question. If you believe Piketty has written a largely rhetorical position paper, then sure, why question. However if Piketty is endeavoring to to do evidence-based formal social science questioning is not only appropriate, it should be welcomed.
Is it really that cute? For example, I get the WSJ delivered daily because I value it's top-notch reporting and journalism. But, I usually skip its editorial pages: their editorials are written by people with strong ideologies and lots of rhetoric - things not very interesting to me. Similarly, FT is probably a top-notch news paper, but should I consider their editorial staff's opinions any more than the WSJ's editorial writers'?
I guess I have a bias against editorialists and a bias toward scientists, researchers, historians.
Furthermore, I am more surprised that more editorialists haven't slammed the book. I mean, given the book's subject and conclusions, I would have expected an avalanche of criticism, by now.
See http://en.wikipedia.org/wiki/Arming_America as an example why questioning is necessary.
(As it happens, I don't believe any of the critiques so far have undermined his main results.)
Finally, your analogy is poorly informed and too cute by half.