You will find the members of the invisible church working to do the very things that God commands. They are working to prevent this type of horrible abomination.
This distinction is useful for a many theological issues but not, in my opinion, very helpful for clarifying matters of public witness. It's similar to the die-hard Marxist, watching the changes in Eastern Europe and the former Soviet Union, continuing to insist that those countries didn't practice real socialism or real communism, and so their failure doesn't mean much.
Non-believers should be able to accept, more or less at face value, the public everyday witness of the visible church rather than be asked to first accept the visible/invisible distinction.
Otherwise, all that happens is that the question simply shifts to: Why don't individual members of the invisible church, i.e. true believers, publicly rebuke, and call for the repentance of, visible church leaders who teach falsely and ignore the plight of the widows and orphans? These false teachers' sin is public; so should their rebuke be.
Some may say that invisible church members, by definition, don't have the platforms or positions that visible church members do. That's true, but surely at least some of the visible church leaders are also members of the invisible church. Thus they are not only able but also, presumably, willing to speak out for truth and justice in a public way.
That only a handful of such men is currently speaking out on the wickedness of foster care issue (and, correspondingly, on the wickness of the church for neglecting the issue) is, in my mind, extremely telling. It means that the invisible church does need to repent. Not only of this injustice but also of the equal or greater injustice of permitting the visible church to drag Christ's name in the mud with so little opposition. The real church isn't impotent, after all: "If God is for us, who can be against us?"
The conclusion of the matter, then, is that we members of the real church need to (1) repent of blaming others for our disobedience, (2) repent of that disobedience, and (3) start obeying again. If we do that, we'll quickly recapture those parts of the visible church worth saving, and God will bring destruction on the rest.
And threads like this on Free Republic will receive considerably more attention than they do presently.