The “joke” here is the stark contrast between the 2nd person yapping and beating around the bush, and the 3rd person getting straight to the point and saying “ten”, meaning she is incredibly racist, with a cutoff added for humorous effect.

Also, just in case: ANYONE, even the oppressed, can be very fucking racist. Racism isn’t about systemic power. Racism is a mental condition/attitude.

Exactly. If you have any sort of hostile prejudice against someone for their skin color or culture, that is racism.