“How does one stop these sites from extorting 39.95 to remove the record of the arrest?”
A well designed and enforced law is the only solution. That comes from someone who thinks at least 50% of existing laws should be repealed.
Technology is way ahead of culture and law and it might be to late to do anything about it.
Anything you have ever posted to the Internet (even for 1 second), is there forever.
If people realized how much information Companies and the Government have about us people would freak. Knowledge is power.
The funny thing about big data, is like subatomic particles, when it's being observed, it changes.
So when people finally do become aware of the dangers, they'll either stop posting their opinions and activities online, or post neutral drivel, which latter would not be much fun for them, so maybe they'll stop online activities altogether and get a real life, which is what they should have been doing all along.