Then it means that people are responsible to themselves to fix their gullible nature
But people aren't responsible for taking advantage of gullible natures?
The term nature to me implies that it can't be fixed, because that IS their nature.
Every man and woman and child for themselves! Cooperation and support are for weaklings.
More seriously, it seems like you have an uncommon view about good ways for people to relate to each other. You may recall that humans evolved to live in large, cooperative groups :)
There is a difference between allowing free agency while creating an environment to steer people away from bad things, versus banning said things.