Well, they can. As a matter of fact, Indians can smell White people.
5 seconds sound clip from the Hondo (1953) movie soundboard.
You can hear this line at 00:14:41 in the Blu-ray version of the movie.
Quote context
[...]
- Then you get the Indian to beat the puppy with a willow switch four or five times a day.
- And when he grows up, he'll always signal when he smells an Indian.
- Well, they can. As a matter of fact, Indians can smell White people.
- I'm part Indian, and I can smell you when I'm downwind of you.
[...]