Neh. Perhaps the initial communication from the broker was along the lines of "Here's the deal I cut for you. The distributor is going to place several orders that together are going to add up to 6000 units."
"Great, we can do that... sounds good"
Now, the actual orders come in and the language is more concise and doesn't use industry jargon. The actual purchase order probably says something along the lines
500 cases regular (6 bags per case) * $40/case = $20000.
500 cases decaf (6 bags per case) * $42 = $21000
Total order: $41000
They get the first order like this and they say, great, that 1000 units. We should probably expect 4 more orders roughly like this. When they got more than 5 orders like this, they started to freak out.
For your assumptions to make sense, the initial language had to match up to the PO language, which I wouldn't think it necessarily the case. Not being in the food industry, I can 100% imagine how one would assume units to be bags of coffee. I can also 100% see how people well versed in the industry would know that units means cases. This is obviously a rookie mistake and I'm not even going to claim that these are astute business people, but given a kinder interpretation of events, I would say moron is a strong word here.