Why Is It Almost Impossible for Morocco to Get Ceuta and Melilla?

Many factors hinder Morocco from getting Ceuta and Melilla. In the Spanish mind those two cities are considerd Spanish as Algeria was once considerd French. Also, the demographics are in favor of Spain: The ethnically Spanish people who were born there consider their birhplace as the hometown and if Morocco acquires them what she will do to those dwellers? Also Spain invaded the enclaves many centuries ago when modern-day Morocco didn't exist. It seems that history wiped out all the Moroccan calls for sovereignty over the two lands.