It is indeed very true that smart people --or indeed any people–saying something is so doesn’t make it so.
OTOH, if something IS so, it is going to be so whether you, or I, or the Dalai Lama, believe it is so.
We have to be careful not to be too prejudiced. And we also have to be careful that we aren’t too prideful. Because while I don’t consider that “just because Pope X said so” is a 100% guarantee that something ‘is so’ because it is a “Pope” who said it. . .I must note that, because Christ said such things as “You are Peter, and upon this rock I will build my church, and the gates of hell will not prevail against it”. . .because of other scripture, because of sacred tradition, and because of the Holy Spirit, when it comes to matters of faith and morals, when it comes to matters of teaching which are part of the deposit of the faith, if Pope X says so, it is because he is Vicar of Christ and He is saying so through the charism of infallibility given by the Holy Spirit, through which the Spirit guides us to all truth.
So I’m not just agreeing with something because ‘smart people say so’ or “he’s the pope so I have to”. I will agree and believe because GOD said so. My shepherd is the Lord; there is nothing I shall want.