This was already explained...
SO6P was said to go around, teaching the ways of ninjutsu. When he came across the 10tails, he couldnt defeat it, so he sealed it in himself. Before he died, he knew that the 10tails would manifest itself into the world, he didnt want that. So he divided the 10tails into several "smaller?" weaker forms. He never intended for them to be treated the way they were. Thats why Son Goku obviously shows a high level of respect for him.