Not everyone grasps the contents of the message immediately. Discussion often helps to clarify what was said. Paul's long sermon at Troas led to Eutychus' falling asleep and tumbling out of the window. Lack of preparation leads to lack of learning. Participants who lead the discussions off on tangents can disrupt and confuse the others.
Argumentation has no place in worship services.
Love does not argue and seek to have its own way. Few have learned to allow others to believe a little different than they do. This should be our attitude in every group Bible Study. Not listening to others results in not learning, with zero benefit to you and others. The study has been only a forum for your own ideas, not a learning session for new ideas.