First of all, EVE is a world of racial and cultural divides. The prime fiction paints people groups with a broad brush.
So when you talk about the culture of a corporation or a place, the main actors are going to exude the predominant ideals. Sure, you will have social outcasts who may find a limited success if they have a particular talent or use, but I assume they would mostly act behind the scenes.
If you are someone (like me) who uses the Japanese as an example to inform you of possible Caldari cultural notions, then I would agree that at least cultural uniformity, if not racial uniformity in the State is preferable to having to deal with those who may offend the sensibilities. You get a taste of the cultural divide in that chron about the sneaky Gallentean trader (name?), and the retconned
Deteis description in the Evelopedia supports the concept of a rigid Caldari social structure.
I can still remember during my brief trip to Japan the astonished looks of the old men on the train. I could see the imaginary anime bubble over their heads, "Hey! What is that white guy doing on my commute!" It was far from a 'rural' community, yet surprisingly homogeneous.
I imagine that in any rigid culture, such as those of the Caldari and the Amarr, you would find little diversity of employees, with only a few outsiders who had the skill and interest in mastering and conforming to the culture. Gallente and Minmatar conversely appear more open to working well with different types. I'd be interested to hear differing perspectives.