I thought we were free to trade gold and silver amongst outrselves. Isn’t gold and silver “legal tender” by default?
You can. In fact, you can even create your own "legal tender". Casinos all over the country do just that. There are many resort municipalities that have their own "currency" that is unique to those towns.
This guy ran into problems because he created a coin that looked too similar to an actual US coin. Like I said, it's not the coin itself that's the problem (or the fact that it's gold), it's its appearance that caused him legal grief.
"Isn’t gold and silver “legal tender” by default?"
It can be, but it's not US legal tender.