If the almighty is the creator and all powerful and wise, there is no need to prove anything to humans. According to the watchtower he's very insecure.
Yes, exactly!
I think the ridiculousness of this particular Witness belief is highlighted by an illustration (from the Bible Teach book) that they use to explain it:
Imagine that a teacher is telling his students how to solve a difficult problem. A clever but rebellious student claims that the teacher’s way of solving the problem is wrong. Implying that the teacher is not capable, this rebel insists that he knows a much better way to solve the problem. Some students think that he is right, and they also become rebellious. What should the teacher do? If he throws the rebels out of the class, what will be the effect on the other students? Will they not believe that their fellow student and those who joined him are right? All the other students in the class might lose respect for the teacher, thinking that he is afraid of being proved wrong. But suppose that the teacher allows the rebel to show the class how he would solve the problem.
Jehovah has done something similar to what the teacher does. Remember that the rebels in Eden were not the only ones involved. Millions of angels were watching. (Job 38:7; Daniel 7:10) How Jehovah handled the rebellion would greatly affect all those angels and eventually all intelligent creation. So, what has Jehovah done? He has allowed Satan to show how he would rule mankind. God has also allowed humans to govern themselves under Satan’s guidance.
The teacher in our illustration knows that the rebel and the students on his side are wrong. But he also knows that allowing them the opportunity to try to prove their point will benefit the whole class. When the rebels fail, all honest students will see that the teacher is the only one qualified to lead the class. They will understand why the teacher thereafter removes any rebels from the class. Similarly, Jehovah knows that all honesthearted humans and angels will benefit from seeing that Satan and his fellow rebels have failed and that humans cannot govern themselves.
Something like this happened a few times when I was in school. In most cases the teacher just told the student to sit down and be quiet. Sometimes, the teacher would hear the student out, but only if the student was sincere and needed a better explanation of the material. I could never imagine a teacher allowing one of the students to confuse the whole class with something they knew was wrong to begin with.
None of the other students felt that one of their classmates knew better than the teacher and they would even get annoyed by the interruption. We had enough confidence in our teachers' knowledge and experience.
Still, the teacher wasn't perfect and it was possible that the teacher was wrong and the student was right. Of course, with an omniscient teacher this would never be an issue.