Who do you think is going to put the fetters on capitalism the Pope call for?
“Fetters” are either internal or external.
Internal restraints are “imposed” by the individual on himself as a matter of morality and responsibility to God.
External restraints are nothing but force or the threat of deadly violence in order to coerce behavior.
You can try to convince people to comply with the former, and that’s entirely moral, but if/when you fail, and attempt the latter, you’ve become a thief at best and have put yourself in the position of God at worst.