Domestic sphere should be kept private?

When one parent has a well-founded fear that their former partner is abusing or neglecting their child, however, evidence for the courts can be hard to come by. The domestic sphere is largely opaque to the outside world. That is how it should be for the most part—invading the privacy of that sphere is usually unwarranted.

Now this statement is obscure at best and misleading at worst. Does the author intend for us to believe that spying is okay if it is done for a reason? Or is it only fathers who are allowed to do so? Or is this to state that ALL domestic issues (home life) should be kept private? I am sure these abusing and battering men would love that.....