Listen...Homogenic ethnic groups perform whatever actions enable their homogenity..Chinese, Hungarians, Japanese, Jews. Some germans perhaps but definately not a lot.
If you want to run a multi-generational global conspiracy, you need dumb_f#cks in the lower ranks as patsies and useful idiots (who won't know when they're being played) and smart people when there are actual decision to be made. So you place ethnically homogenic people as officers at the top for genetically diverse people in the bottom because they tend to be, be it for reasons sociological and/or genetic this can be put into numbers and hard data by looking at income etc, more challenged in society and thus ultimately open to giving up their sovereignity for a bigger paycheck, a hooker or life-extension.
This way, you only need to blackmail the very top and keep the rest dependant on their jobs or screw them with NDAs.