Maybe they ask themselves, "What is a sermon?"
The simplest answer: a speech. One talks and many listen. The purpose of this speech is to make the old texts of the Bible understandable. This includes answering the question: What does such an old text have to do with me and my life? Anyone who seriously asks this question will be surprised at how up-to-date the Bible is. This speech also wants to give impulses like our life (with God) can succeed better.
How is that meant? Here is a comparison: If you buy a technical device today, this is an instruction manual. It explains how to operate the flat screen or the navigation device. Without such a manual one sometimes looks quite old. Life is even more complicated than any technical device. Why not give yourself the occasional help and suggestions, so that it works better?
Wikipedia gives the following definition of the sermon:
sermon (lat. praedicatio) is a speech in the context of a religious ceremony, mostly with a religious content. The sermon has a special place in the New Testament and in Christian worship. In Christian theology, the teaching of sermon is called homiletics. Sermon in English and French means "Sermon" (from lat. sermo: change of speech, conversation; lecture).
Bryan Chapell writes in his book "Christ-centered preaching":
Every text of Scripture should be related to the grace of God through Christ. Some texts prepare for Jesus by representing the salvation need of man. Other texts prophesy the coming of Christ. Still others reflect facets of salvation in Christ. And yet other texts are the consequences of salvation in Christ, namely the manifold blessings through the grace of Jesus. Here are some texts like seed, which has not yet risen. The connection to Christ is recognizable when viewed from the New Testament perspective.