After looking through the evidence, both, but moreso the second.
Ea-Nasir's tablet is dated to 1750 BC, which is coincidentally aligns to the death of Hammurabi. For context, he lived at the end of the Isin-Larsa Period, a time in Babylonia's history where it was a collection of warring city-states. Ur and Larsa were the most powerful of these, since they were farthest south and controlled most of the trade coming up the Persian Gulf. (Isin, near where Hammurabi was from, was in the North and had lost power about 200 years before.)
Right after Hammurabi's death, all the city-states he'd conquered, including Larsa and Ur, decided that they didn't give two squats what the people in the North thought, and started a rebellion.
- Ea-Nasir was hot-headed. 3 tablets note him talking rudely to messengers and traders.
- Ea-Nasir sold copper to private merchants AND the temple, which was the government of Ur. The receipt we found is in such a large quantity we can assume the government was likely his primary buyer. The complaint tablets are from notably from private merchants.
- Ea-Nasir was an alik-Tilmun; or 'one who travels to Dilmun'.
Where is Dilmun? Good question! Archaeologists spent the next 40 years figuring it out! At this point, they're fairly certain it's in present-day Qatar. The city was used as a midpoint port to bring in copper from Magan and Meluhha (current-day UAE/Oman and India respectively.)
The reason we know this, is because Oman is an old, old copper-producing region. It's an ophiolite (rock from the seafloor that's been uplifted to the surface) that contained a spreading center (think Mid-Atlantic ridge) which forms deposits of copper and other metals as sulfides from the black smoker vents (copper-iron sulfur, lead sulfur, zinc sulfur, etc.)
To produce copper, you have to remove the iron and the sulfur. To remove the iron, you add "flux", which essentially bonds iron to silica, because it likes silica more than copper does. And to remove the sulfur, you add oxygen, which burns off the sulfur as gaseous SO2.
The copper is heavier than the iron and silica, and sinks to the bottom of the furnace. The iron and silica, slag, flow out the side. The resulting ingot looks like the bowl below. And a lot of times, holes remained from gas getting trapped at the bottom.
They measured copper by weight though, so this wasn't too much of a problem. However, if there weren't enough flux, or the fire wasn't hot enough, iron would also get trapped in the copper ingot, making "black copper"; if a merchant wanted the 97% pure copper that could be made using this process, a lot of iron would definitely be considered 'bad copper'.
Switching back to the culture!
Around 1800 BC, the same time as this was going on, the culture of Oman underwent a noticeable decline. Many of their coastal mines stopped producing copper and people moved inland. They also stopped making bronze with tin. This is notable, because tin was scarce in the Bronze Age and insinuates they might've been left out of the trade route. At the very least, they had stopped being Mesopotamia's primary supplier and started doing their best to keep up with the times.
(At this point, I'll point a finger to Cyprus, which was firing up its smelters at the same time. Cyprus is very interesting, but it pertains less to Ea-Nasir, so I'll just wave enthusiastically at their oxhide ingot copper and tin trade domination.)
So we can't know if Ea-Nasir wasn't a chronic scammer, but I think all the evidence outlines a different story.
Ur, a powerful city-state rebelling against a conqueror within Ea-Nasir's lifetime. Ea-Nasir, selling large amounts of copper to the government, and smaller sales to private merchants who complained about being given scraps; a man who was still traveling to trade copper in a state that had lost their monopoly on the copper trade and was possibly producing some less-than-ideal quality.
He mostly sounds like a person with strong ties to his city and culture. Maybe not the best copper merchant, but certainly a passionate one.
References below the cut: