I never really saw signs of overt racism in the congregation I grew up. Granted I lived in an area with lots of universities and diversity, so that could help.
The only thing that could qualify was during the big annual Spring and Fall cleanups at the KH. The members of the Spanish congregation would show up to help in droves, which sounds good except that most of them were unfamiliar with even the most basic landscaping and simple construction and maintenance tasks (e.g. raking out garden beds, mowing the grass, painting, etc.)
Most in the English congregation chalked it up to the fact that most of the Spanish congregation was rather poor, and almost none were homeowners so they didn't grow up doing yard work and working on their own homes.
Frankly it made everyone's job a little harder because the Spanish friends would struggle through the assigned tasks rather poorly, necessitating the friends from the English hall having to closely supervise, coach, and re-do much of the work. There was a measure of unspoken resentment on both sides, I think.