"Now, I had lived in Washington, D.C., partly so I would be in the minority for a change..."
How big of her.
Gump seems to feel guilty about "trampling all over" the fine line between taking a "sociological field trip" and attending an event earnestly. My, what a pampered life she must lead to have such fussy concerns.
Maybe the reason they shunned her is that she acted like a patronizing jerk or made them otherwise uncomfortable. Maybe the other people were simply racist jerks. Or maybe both.