OriginofSin, when you refer to someone as an idiot or think of them that way, you are refusing to respect them. If you want to make a point with someone, consider them as intelligent human beings and treat them with respect. You will get a lot further that way.
Yes, God knew the angels would rebel. He also knew we would. That is why we read in Revelation 13:8 that Jesus is the Lamb slain from the foundation of the world. God had the answer prepared before the problem occurred. He always does....smile.
Why did He allow rebellion when He knew it would happen? Because worship and love and obedience are not real if they are programmed into something or someone. They mean something when there is the choice to not worship, or not love, or not obey. And the minute that choice is there and real, some will opt for it.