One band must be 1st and one band must be 10th. It has to be this way. First place trophies are expensive and they only had money to buy one of them. This does not always mean that the 10th place band was a lot worse than the 1st place band. Marching contest results could truthfully carry similar advisories.
All artistic judgments are subject to subjectivity.
Even the best judges do not always agree. One judge may be more concerned with intonation while another will care more about ensemble. These are not evil biases. These are legitimate artistic differences. At some contests, you get judges who tend to pay less attention to the particular weak points of your band and at other contests you don't.