Jesus used this figure of speech, but they did not understand what he was telling them.
The Greek word (paroimian) translated as “parable” in KJV is not so translated anywhere else in the Bible and is not the same word which is translated as parable elsewhere (parabolh). The NIV better translates it as “figure of speech.” It could also be translated as “simile.” It literally translates as “beside the way” and means a wayside saying.
Why don’t the religious leaders understand what Jesus is telling them in this simile? Probably for two reasons. First, it goes against their concept of what God is like. They cannot conceive that their God is in fact loving and caring and acts like a shepherd to them even though He has said exactly that throughout the Old Testament. Second, the other part of the simile is speaking of them and they would not want to understand that they were at fault and were compared to robbers in the way they deal with God’s people.