Why should scientists debate the results of a scientific experiment

Because, I might get one thing for an answer, and you might get another. So you run multiple tests, and we compare our answers / conclusions.

And if both tests are different, we do it again, for maybe a 3rd or 5th time, then we would debate our conclusions, again.

Basically, make a poll, and see which one of us gets more agreeable answers.

They should debate because the experiment result can differ from the first time. This is why you should always do your science experiment twice. Also it makes the scientist better so that they can improve in the future.