I don't think it's really a gentleman's agreement Bear Backer. I think it is controlled by the reactions of DWFs, CaucasianRivals media and the locker room dissension that could come from any racist blacks that were on a roster that was half white or more. These reactions very well could cost the coach and GM their jobs from the scorn the team would get.
Here is an example of the type of the idiot DWF with peanut butter for brains that keeps an NFL roster from becoming half white or more in our 75% white country: There was one poster who started a thread "Larry Bird= Tweety Bird" on the CBS message board. The thread was about Bird's supposed "favoritism" toward white players and how Hansbrough is crap. This is even though the Pacers are slightly less than half white, but very close and Hansbrough tested well athletically and is the all time ACC leading scorer.
Here's another example (I think on CBSsports again or maybe Scout.com): An idiot fan said that Eric Weddle sucks and the reason he makes tackles is because he's always out of place and beat in coverage. A CB making tons of tackles might not be a good thing. However, this idiot doesn't realize that a tackling machine safety like Weddle saving TDs for San Diego's overrated second CB (and the fact that the opposing QB had all the time in the world to throw last year with no Charger pass rush) was a savior for them. So now a safety (not a CB) leading the team in tackles in his first year starting makes a guy suck?
Example 3: Two other idiots in an Iowa forum stated that Brad Rogers could be as good as Wegher. These guys must be nuts. The chances of that are about 1 and 100,000. Wegher ran for over 3,000 yards on 9 YPC as a senior and runs a 4.4 40 and has run a sub 4 short shuttle multiple times. Wegher's highlight tape is also out of this world good.
Meanwhile Brad Rogers ran for 5 YPC in his H.S career and had less than half the yards of Wegher's senior season in an entire H.S career. Rogers is a bit overweight, runs a 4.65 40 with a plodding 4.5 short shuttle and had an unimpressive highlight tape. But somehow Rivals rates this scrub as high as Mike Trumpy and the DWFs like the guys I aforementioned are buying the hype. What a joke "football" fans in the U.S have become, are they really this clueless.
I will edit and post links tomorrow to these threads, the links are saved on my other computer I believe.