The Great Jihad ?

Ron: Young children are very much like prisoners of their parents.  They are given very little freedom at first, and they are under constant surveillance.  And yes, they may be punished if they disobey.

Such a young child is likely to obey only out of fear of punishment (which itself is because of their lack of understanding as you also said), but loving parents do not punish to benefit from it nor to feel better.

I would simply remind her of the real reasons why her behaviour was bad  (e.g., if you don't eat your peas you won't be healthy), and leave it at that.

In Monotheistic religions, as an example, God simply reminds people to not worship pieces of stones carved by human. He reminds them (through His prophets) that the stones are not alive and can not even defend themselves so it is a waste of time worshiping them. This is a clear simple real reason, isn�t it?

It seems to me that God continues to treat people as children.

Through His last prophet, He has completed what people need to grow otherwise He would not send His last prophet. However, in contrast to this accomplishment, it seems many people continue to refuse the truth childishly.

Worse, actually, because to be effective, penalties must be given as soon as possible after the offense in order to change behaviour.

Ron: And then, much later and after it is too late for the idolators to correct their behaviour, then he roasts them in Hell for eternity.

Only one of His prophet (Nuh (as)) was trying to convince them to correct their behavior for about 1000 years. After him so many prophets with miracles and clear evidences and reasons tried in different ways but those who did not want to change did not, that was that. However, who has told you that in the other world all of the idolators will be necessarily in Hell for eternity? As much as I know from Islamic opinion, eternity is not for all of those in Hell.

Look, if He really doesn't want people worshipping idols, all He has to do is to make every idol burst into flames or melt into a puddle of magma the moment anyone tries to worship it.  It wouldn't take long before people got the message.  It would also be irrefutable, reproducible, scientific evidence that God exists.  As I've said before, if God really cared whether we believed in Him or not, He could do a much, much better job at getting His message out.

I would say in such a case God had to destruct everything as people has worshiped everything from moon, sun and human to animals and other things.