"...ban buying textbooks from them."... you mean from Texas?

It's not 'from them', it's that they buy so many books that they affect what gets published & printed.

"Decisions by the board — made up of lawyers, a dentist and a weekly newspaper publisher among others — can affect textbook content nationwide because Texas is one of publishers' biggest clients."

That situation affects all of us, whether we live in Texas or not. Authors of many textbooks tend to tailor the details to suit what will sell, and when there ARE competing authors and books, publishers simply don't like to publish ones that have fewer customers....and you'd better believe that conservatives in Texas are aware of this! I lived in Kansas, and we sure saw many of those...