The graphic and the teaching:
Some people have looked at the graphic and the the teaching that accompanies it, which Chabad.org posted on Facebook, and have seen a lone Jewish woman studying a Jewish religious text in a subway car otherwise populated only by African Americans, and understood the teaching and graphic to mean that African Americans are impure, and that their speech and their thoughts make the air – the atmosphere – in that subway car impure. The remedy for that, Chabad seems to be saying, is the Jewish woman's Torah.
If the other passengers on the subway had been a mixture of ethnicities, the teaching would be somewhat less offensive, because it would be implying that all non-Jews, rather than just African Americans, cause spiritual impurity.
But even that is offensive.
The idea that non-Jews cause impurity is itself offensive.
Ah! But Chabad will respond that the "air" of the Land of Israel is pure because the Land is holy, but the "air" everywhere else is impure because the entire earth outside of the Land of Israel is not holy (and by definition impure).
But that is really no different than saying that non-Jews are impure or that they cause impurity.
Chabad hasidut contains some extremely bigoted anti-gentile teachings. (For example, non-Jews' souls have "no good in them at all," according to Schneur Zalman of Lyadi, the first Chabad rebbe who is commonly known as the Alter Rebbe or the Ba'al HaTanya.)
But what Chabad has done here, intentionally or not, is to make the focus even narrower. It is African Americans who are "impure," and it is their "air" that needs to be "purified" by the Jews and for the Jews.
This may be accidental racism, but it is racism nonetheless.
[Hat Tip: DovBear.]