The petitioners state that at some point during the production of child pornography either a child or children have been victimized, that child pornography hurts children, that it can never be justified and that the possession of child pornography perpetuates the production of children pornography.
Child pornography is the cause of children being victims when they are in it.
It clearly states that children involved in it, are victimized. I think the system didn't connect that a child 'being in it' connected with the 'production'.
( z1 cause :ARG0 ( z2 pornography :mod ( z3 child ) ) :ARG1 ( z4 victim :domain z3 :time ( z5 be-located-at :ARG1 z3 :ARG2 z2 ) ) )