This is a brilliant insight. It reminded me of an unfortunate incident that happened on the last days of Pesach with an African-American woman that my wife and I have been helping to prepare for giyur, and her already-meguyeret sister.
A friend of theirs made arrangements for the three of them to spend the last days of Pesach at the home of a family in a large frum community. It so happens that racism, particularly toward blacks, is epidemic in this community. The friend who made the arrangements, herself a ba'alat teshuvah, did not think, in her naivete, that the skin color of her two friends would be an issue. It didn't even occur to her to mention it. She simply asked if she could come for Yom Tov with two friends, one a giyoret, and the other, her sister, well on her way.
The way these three women were treated served as a very rude awakening for the ba'alat teshuvah, but the sisters took it in stride. They were basically treated as second-class citizens, seated at the end of the table, below the children. They were even explicitly told that they had been seated 'below the salt'.
Had I not grown up in such a community, I would have felt, like their friend felt, shocked and outraged. Instead, having spent years trying to get that native bigotry out, I am simply ashamed.
Though there are other explanations for Miriam's sin in our Parsha, this lesson remains one that we can stand to learn a few more times.