"If your hand or your foot causes you to stumble, cut it off and throw it from you; it is better for you to enter life crippled or lame, than to have two hands or two feet and be cast into eternal fire."
Jesus discusses a subject that is not talked about much in our day because we see all desire as good because it is natural. But Jesus clearly states in this verse and the one above it that there are desires that are evil and wicked and should be stopped or limited so that they do not happen. There are clearly desires that arise in the heart of mankind that should never see the light of day. The impulses to harm a child are toxic to the individual and to the society. If they are allowed out into the open, they will condemn the person and the society.
A society cannot allow or permit, in the slightest, people to give into the impulse to abuse children. It is a toxic stream that will pollute a whole culture. Jesus says that these impulses will continue to exist, but that they must not find an outlet through an individual person. Woe to that man through whom they come.
Jesus even goes so far as to say whatever you have to do to stop yourself from acting out the wicked impulses that arise within you to harm a child should be taken. Don't allow yourself to act on those impulses.