Tadlock knows that no other form of justice will do for the Indians if the wagon train is being pursued by them out of vengeance, so he hangs Johnnie, for the safety of the traveling party, but to their outrage.
Tadlock understands that no other form of justice will suffice for the Indians if the wagon train is being pursued by them out of vengeance, so he executes Johnnie to protect the travelers, but to their dismay.