Help needed: somehow still confused about wholesalers vs distributors?

This is most a technical question. I figured, instead of emailing Alyssa directly, I'd ask it here, in case others are confused about the same thing.

So, in preparation for Vegas Foam, I'm getting ahead and just finished reading Thursday's case. One thing in particular really confused me, which is the constant appearance of the comparison between a wholesaler and distributor. 

Now, according to the explanation in previous cases including the New Vine Logistics one, in the US, distributors AND wholesalers make up the same layer in the three-tier (see screenshot from case below). 

However, in the WineInStyle case, there are comments such as the following:

"Exporting from the United States remained a grey area, as it was unclear whether a distribution license governed export activities, or whether only wholesalers could export wine"

Also

"In the United States, states regulated the sale of wine, while distribution licenses were issued by the federal government. This led to a plurality of wine distributors in the United States, and a near-monopoly of wholesaling by a company called Southern Wines, which dominated wine wholesaling in over 75 percent of the wholesale market. In Japan, one federal license each governed both the distribution and sales of wine."

Now, these two quotes above made it seem as though, in the US at least, wholesales and distributors are in fact different.

Could Alyssa or anyone else please shed some more light on this? I thought I understood how wine is sold in the US after the millionth time of Alyssa explaining it in class but clearly I'm still missing something here.

Thanks!