It's not surprising that this happened.
I am surprised it took this long.
As a homeschooling Dad, this type of behavior on the part of the various "child protective services" (different names depending on state, county, etc) is pretty common. With their anonymous tip system, anyone with a beef can sick these people on you at the drop of a dime with absolutely zero repercussions for false statements. They perfected their verbal delivery in order to challenge you on a moral basis to prove your innocence and invoke you to violate your own rights without thinking about it. For most honest, law abiding people, who are not aware of these tactics, they openly allow them in the door because they have nothing to hide. Their very confrontational delivery methods make you doubt your legal ground all the while making very threatening statements if you do not comply. It's pressure sales at its worst! I am glad the individual in the story had a lawyer readily available who could advise him and his method of mounting such a defense. Huge kudos!
The doorway is the front line. It's hard to get them out once they are in. Without a warrant, you would think they have no legal jurisdiction to get in. I recall at least 1 case where law enforcement, accompanied by a CPS social worker, barged their way into a home against the protestations of the homeowner as the LEO barked he didn't need a warrant if there was a reported crime in progress (a family feud over how Grandpa was being treated in the home of a sibling, who also homeschooled, which resulted in another sibling calling to report abuse). In that case, the "tip" was completely false, the homeowners rights violated, and I need to check on the follow up as I think I remember a lawsuit stemming from it.
The soundbite they operate with is they are "protecting the children." Who wouldn't want to go along with that? The "urgency" and "moral imperative" of their cause coupled with little/no operational oversight makes them ripe for abuse. I believe the LEOs in these scenarios are unwitting participants in the play, as the CPS is the one pulling the strings and the soundbite is so urgent.
Don't get me wrong, child abusers deserve punishment. But trampling the rights of innocent gun owners or homeschoolers because of an anonymous, unsubstantiated tip is absurd!
In the HS world, an organization called Homeschool Legal Defense provides lawyers to battle these offenses the same way as this played out, providing services via phone and interposing themselves between you and CPS/LEOs. I wonder if this behavior continues against gun owners, if there won't be a need for a Gun Owner Legal Defense.
I hope it doesn't get to that.