That case is in regards to a guardian figure who has some level of legal responsibility for the children in their care. In that case it makes sense to hold someone accountable for the actions of someone else because the person in question agreed to that when they became a guardian.

Software developers should not be held liable for what their users do with the software unless the software itself does something illegal (such as malware that gains unauthorized access to secure systems). If developers were responsible for their users then you would have all kinds of bizarre lawsuits. You would be able to sue Microsoft for things written by users in Word. It wouldn't be a stretch to sue Linux contributers because someone used the OS to perform a DOS attack or to host a scam site.