WHile I'm not surprised by the smaller Amarr crew modifier (I don't believe there's actually any proof behind the "wastefull slave labor aboard ships" thing), both the Caldari and Minmatar ship modifiers surprise me.
While the former could be at least partially explained as being caused by a higher density of interactive systems in the hull (the Amarr and Gallente bother burn large volumes of hull on thick armor plating; the Amarr may have large, luxurious quarters for higher officers, the Gallente may be spending room on internal drone storage and automation systems, etc...). Furthermore, I'm fairly sure the Caldari Navy has been described at times as the smallest, if the highest-tech navy, so having high concentrations of crew aboard extremely valuable ships isn't such a strategically poor choice.
Minmatar hulls, on the other hand, are often obviously smaller than their counterparts in other races in terms of internal volume (compare, say, the largely "empty" structure of the Breacher hull to that of the relatively large Kestrel or Tristan hulls), nor would they have the hugely complex (and thus oversight-demanding) resources of the Caldari, so I'm not sure why they need so many crew. Perhaps they lack even basic automation features the Amarr and Caldari have instituted, let alone the advanced drone systems of the Gallente?