The whole point is not the difference about Obito but rather how far someone would be willing to go to make sure the enemy doesn't get the intel. That's part of the basic concept of missions since intel is practically the gold. Similar with Zabuza just wanting some money and he'd kill a group of pre teens and Kopi Ninja Kakashi. That's why I commended Kisame as a true ninja because unlike Naruto or Sasuke, he and Zabuza (and Itachi) represent the meaning of shinobi.Well here's the thing. Even if they knew it was Obito. They would never know what his current powers are till they fought him. Cause the Obito Kohona knew was the little boy Obito.