Board Thread:Episode Discussions/@comment-1181222-20170802095306/@comment-35622277-20170806083205

It doesn't matter if he couldn't justify his ban of the Kote at all, the bottom line is that he banned it. He is the Hokage, and whatever he says is prohibited, is prohibited. Doesn't matter if people think it's unreasonable, Naruto has final say.

Boruto used something that was prohibited, got caught, and was thus disqualified. Plain and simple.