Where, and please be specific, have I been shown that Parables stem from true events? Who am I kidding, you will ignore this question as you ignore any and all questions that you either have no answer for or that show that you have caught in a............oops: I can't say what you do often here since you cry to the moderators when you are called out on your behaviour.
But all the readers know, they know.
Although you seem to invite this sort of thing even though most would be embarrassed to be shown to contradict themselves, here is material from a site you provided:
By definition, a parable is a true-to-life story used to illustrate or illuminate a truth. This is true even if all of the details never occurred exactly as presented in the story. They are special stories that may, or may not, reflect historical events. Nevertheless, they must be true-to-life. By true-to-life we mean that a parable must be based on a real-life situation that the hearers are familiar with. In other words, the story itself has to be based on events that could have happened, whether they ever actually did or not.