1) He believes that men are only happy in slavery. Also, they need the feeling of being forgiven no matter what. The church should take the sins of all mankind unto the themselves and relieve all mankind of their burdens.
2) He does not understand that humans cannot have freedom. If they have freedom, they will only suffer. Also, Jesus does not understand that humans need to feel forgiven no matter how dreadful the act they performed was. Only then can they live in true bliss.
3) They can take the sins of man unto themselves and help mankind believe that they are truly forgiven.
4) When man is free, they live at their own expense. So they make their own mistakes and are held responsible for those mistakes. If man were under the complete control of some other power, mankind would follow their set lifestyle and would make only the mistakes that they were allowed to make.