[pm3003]

He's not saying it's false, but he's referring to the fact that the religious dimension of the Crusades has been occulted by a lot of 20th century historiography as incomprehensible and necessarily false. It was rather presented as an excuse, and the Crusades were even considered by some a precursor to European colonialism, driven by economic gains, overpopulation etc.

This unbalance is the historiographical mistake, as would be (according to the article) the lack of attention for the Baltic or Albigean Crusades, hitherto considered not-much-more-than-local events which were given a religious stamp of approval for various political and financial reasons and thus not "real" crusades.