Equality of opportunity is no guarantee of equality of outcome. Those who offer the opportunity have no control over what you bring to the table nor how much effort you make to succeed.
Nor do I. You'd think these Berzerkeley people would be bright enough to realize that these "poor kids" nonetheless enjoy living conditions superior to that of 95% or more of the U.S. population prior to WWII. That includes the parents of a lot of FReepers, including mine. Yet I will hazard a guess that few if any of us who had parents who grew up dirt poor can imagine that they would have tested as low functioning.
I agree with the poster who suggested that the children have most likely inherited their parents low intelligence. Giving such children "equal opportunity" will not produce the same outcome as in children of high intelligence. Our goal should be to insure such children develop to the best of their abilities... not to have them chase some liberal pipedream.
I believe you're right. It is lack of cognitive stimulation in their environment, (illiterate parents and other care givers).