Switzerland is just much more homogeneous, we do have 4 different languages (with associated cultural differences), but there has never been the sort of tensions or outright discrimination as there has been in the US with black people.
But, having lived in Switzerland for most of my life, I unfortunately feel that there is a very strong undercurrent of xenophobia, to the point that parts of it are even accepted among more left-wing circles.
If you look at the history of Switzerland, there have been multiple civil wars between Catholics and Protestants, from the 16th through to the 19th centuries. So tensions have certainly been there for much of Swiss history.
That ended in the 19th century, however, and in the 20th and 21st centuries, those religious tensions are not what they used to be. (That's not something unique to Switzerland; most European countries, religious tensions people used to kill each other over, nobody cares about any more. Here in Australia, my grandfather told me how as a Catholic in the 1940s, he couldn't get certain jobs because some employers refused to hire Catholics, and the law let them get away with that. But, I've never heard in contemporary Australia of someone refusing to hire a Catholic, indeed nowadays it would be illegal for a secular employer to do so.)
Certainly you are right, that however bad Catholic-Protestant tension may have been in Swiss history, it still was nothing compared to the treatment of African-Americans.
But, having lived in Switzerland for most of my life, I unfortunately feel that there is a very strong undercurrent of xenophobia, to the point that parts of it are even accepted among more left-wing circles.