I'll take advice from anyone provided the advice is right. Objectivism teaches that A is A. Thus if 2 + 2 is 4, it doesn't matter if the devil himself makes that claim, reality will always be reality.
Porn is a choice, like being a Christian, like getting a tattoo (which the Bible condemns btw), like many other choices.
As for the children, worry about your own. Your children belong to you, the children of your neighbor don't belong to you.