TLDR; sending a surplus of tshirts to Africa did nothing but crash local textile industries by introducing a surplus of existing, cheap product. Guy wanted to do good, didn't think about the consequences, and screwed up.
Except you clearly haven't read the article - he didn't send the shirts, he listened to the aid workers and criticism over his plan and decided against it.
The local textile crashes referred to in the economy were from cheap second hand imports, not aid.