Hath not the Potter power over the clay, of the same lump to make one vessel unto honour and another unto dishonour? Romans 9:21
The idea that God makes some people to be destroyed is so offensive to human nature that most won't even consider it. A tip off about their reaction is that it is based on their feelings, not upon the fact that it is plainly revealed in the Bible.
Those who object will use terms like "tyrant" or "dictator" to describe such a God. Soon we are discussing a violation of their idea of God as opposed to how He is plainly revealed in the Word. Their weak little chins will tremble or they may explode with wrath.
"But these are laymen," you may object. Surely theologians can stifle their feelings as they sit in judgement on God. Not only do these birds have strong feelings to consider, but their fame and fortunes are at stake. If they make it too simple, they could lose their positions.
Every major doctrine has at least one chapter devoted to it. So, if you want the plain vanilla truth, just read Romans chapter nine. Then you will understand it. Instead of a tortuous life-long debate, you can quickly resolve this "issue", knock off and watch a Gene Autry movie.