Free will implies the possibility of error, and error in turn implies pain and suffering as its inevitable consequences.
Frédéric Bastiat finds in pain and suffering the raison d’être of the constructivists, whom he also names the “organisers” because they pretend to organise society according to their own conception of what it should be. Indeed, these people are trying and create a structure that would help reaching happiness for all (when they are sincere), which implies the end of man’s suffering. The issue is that pain and suffering, as unfortunate as they can be, are characteristically human and absolutely necessary for progress (“a man who cannot suffer, and who consequently has no wants, desires, sensations…” – this does not mean that pain and suffering should be ignored but in the mind of constructivists, this implies that their views should be forced and that free will of the individuals should not be respected. This is what today’s quote is highlighting.
To turn down responsibility for each and one of us along the risk of error that goes with it requires to turn down freedom while the organiser being human, he is himself prone to error that would then become universal, and therefore much worse, at the scale of the entire society.