I see a selective set of comparisons that all include Texas.
It’s also the case that black kids in the US are going to be in disproportionately poorer areas anyway.
To be more comprehensive and on point, let’s look at differences among white kids.
From here: http://www.ed.gov/blog/2011/09/newly-released-state-by-state-snapshot-of-educational-performance/
Top 10 states white students 8th grade reading proficiencies
CT, NJ, MA, MD, PA, MN, NY, OH, IL, TX
Bottom 10 states:
WV, LA, OK, MS, NV, AL, AK SC, TN, RI
Top 10 states white students 4th grade math:
DC, MA, NJ, MN, TX, MD, NC, CT, NH, CO
Bottom 10 states:
WV, AL, TN, MS, LA, KY, OK, MI, OR, AZ
Four Year Graduation Rate, white students
Top 10: WI, MN, ND, NJ, VT, NE, IA, MA, IL, MO
Bottom 10: MS, HI, FL, SC, NM, GA, LA, AL, AK, AZ
So, one can see why someone might selectively choose Texas in order to misrepresent the state of things; it’s clearly an outlier. The point remains - red state schools are more likely to perform poorly.