Why Did Paul Disapprove The Possessed Slave Girl In Acts 16:16-18?

Ac 16:16 Now it happened, as we went to prayer, that a certain slave girl possessed with a spirit of divination met us, who brought her masters much profit by fortune-telling.
17 This girl followed Paul and us, and cried out, saying, "These men are the servants of the Most High God, who proclaim to us the way of salvation."

18 And this she did for many days. But Paul, greatly annoyed, turned and said to the spirit, "I command you in the name of Jesus Christ to come out of her." And he came out that very hour.

Paul would not accept endorsement from demons even though they spoke the truth about Paul and company. In the end, it would be detrimental to their ministry. People might think that they were in the same company, in league, with each other, undermining their credibility as a result.

Some Say That The Bible Was Not Given To Inform Us But To Transform Us, Is This True?

I am aware of the fact that many are saying that the Bible was not given to inform us but to transform us.

This is false. The Bible was given both to inform us and then transform us. The fact that the Bible was written as a REVELATION from God connotes information. When you reveal something you are, by that very fact, informing.

Our problem is that we don't know God and how to use the life that He has given. And so, we need information from Him. We have absorbed so much falsehood and lies from Satan and the world so we need our minds to be renewed by God's truth.

What we think is most probably what we will believe. And what we believe will most probably be the determiner of our behavior.

Ho 4:6 My people are destroyed for lack of knowledge. Because you have rejected knowledge, I also will reject you...

Ro 12:2 And do not be conformed to this world, but be transformed by the renewing of your mind...