Sorry, but this is not true. You are under NO obligation to give them anything. If you do not want to share what you find you can just go home and leave nothing behind.
You do pay 23 cents for a scan and copy of old records, a nickel for a copy, and a smile to the lady behind the desk who helps you out. Those are all less than cost.
They do collect their 10 percent from their members, of which I am not one.
Some of their online services are not free.