Look as they say, before you leap. As Harry Guerrilla pointed out there is no gerrymandering. Alamo Heights is one of the oldest neighborhoods in San Antonio and its own city, with its own police force, city hall, mayor, etc, etc. When it was established it was considered on the edge of town, out in the sticks. In succeeding generations San Antonio grew up literally "around" Alamo Heights 360 degrees "around" it to draw a picture.
And just for clarification, the term "Alamo Whites" has been a slur/insult, or joke depending upon *context* for a long long time. The fans of Edison who were chanting "Alamo Whites" at the game knew what they were saying and they were not trying to be complementary.
Urban Dictionary: Alamo Whites
Since virtually all reports put all chants at the game as coming from the stands, not the bench or from the teams themselves, blaming the teams and more particularly, the student team members and punishing them for the actions and words coming from the stands is not only grossly unfair, but just plain stupid.
Could you please share a link that details this timeline you speak to?