With our talk about racism in our Mervyn discussion today I thought it would be important to establish some context in that time period.
Here you can find a history of the Haitian Revolution. I find it very interesting that America did become somewhat involved in the revolution. American leaders rushed to help the white leaders when the slave revolt broke out in St. Domingue. Also ironically, Thomas Jefferson (the guy who wrote the Declaration of Independence, the champion of natural rights, who supported the French Revolution, the leader of the Democratic-Republican Party) was put in a political dilemma as he supported the ideals of the revolution but he also had many slaves as well. Therefore he only gave a minimum amount of aid and tried to advocate a compromise. 
Also in relation to the passage we had to explicate(page 274), many refugees from the revolt went to North America, particularly Norfolk (Virgina), Baltimore, New York and Philadelphia. Many of the refugees were in fact white French families who brought their slaves with them. The influx of refugees influenced the passage of Alien and Sedition Acts(xenophobic laws). This may explain Mervyn’s attitude towards the Frenchman and the Congolese women.
Hope you guys find this useful.
Peace,
Wes
P.S. Also found this article discussing the impact of Yellow Fever Epidemic in 1793 on Africans who lived in the USA during that time period. Pretty fascinating.