First thing first, thanks for your hard work !
Now with that being said I'm more curious as how you couldn't see it as such. For one yes the dark skin and clothes might be a part of it, especially since literaly no one else living in the same climate feels the need to dress similarly. But it's not just that :
It's just textbook colinizer narrative, just told from colonizer perspective.
In fairness, as for no one else wearing clothes like them, the only other Mulai citizens we've seen have been the nobles and their servants. These are the only commoners we've seen so it stands to reason they would dress somewhat differently.
I'm still reserving judgment on whether the villagers are going to be explotied. Hesha and Jolene have stated that they want to make a profit but they have never said how much they're actually going to pay for the grapes. They said they wanted them for the price of Perilla leaves, but we have no in world reference for what that value is. Are they worth 1 gold in this world? Or a hundred gold? Even when the villagers quoted them a price double what the villagers usually ask for, Hesha and Jolene still saw that as extremely cheap. Nothing is stopping them from paying 10 times the normal asking price and still making a profit. Would that still be exploitation? Because the line between exploitation and business can be very thin. Ultimately that's who Hesha and Jolene are, they're businesswomen. And this series puts a lot of emphasis on women becoming financially independant and successful.
And I think the reason I didn't really see it as a colonizer narative is that I didn't put any stock into the villagers outfits because that kind of outfit has no real meaning to a chinese reader the way it would for a western one. The villagers aren't an indigenous population being pushed out by some foreign power, they are just citizens of Mulai and subject ot its rule. For me, if the villagers looked and dressed the same as Hesha or Jolene, without changing any of the plot or writing, I could easily see this kind of thing taking place between any number of European countries back in the day.
Imagine someone living in the big city in Spain, they get treated badly so they run away and live near the border with France. They are poor and barely able to get by so they rob a French noble who's traveling along the border. The French noble (seeing a business opporunity) offers to buy the land the Spaniard is living on from the Spanish government and offers to give them a job so they can provide for themselves. Is the Spaniard being colonized?
This series is mostly based on a historical period where countries trading land back and forth, along with the people living on said land, was common place. To me they're just engaging in normal business and politics of the period.
Admittedly I also don't necessarily read Hesha and Jolene's actions solely as a good thing. They are still ultimately doing it for themselves and they've both been shown to be rather selfish, but they don't mind helping out the villagers at the same time in what ways they can. I think the only truly good people we've met so far in the series are Kelly and Arnold (maybe principal Serena, but she was only in like two chapters)
That felt a bit rambley but I hope that made sense.