Eat grass
The United States of America does not have the best reputation when it comes to dealing with the native Americans they interacted with. Some would even go as far as to say that the earlier settlers genocided the native Americans over a long period of time. Needless to say, it’s an ugly piece of history to get into.
There are plenty of figures from this nation’s history who were quoted saying some pretty racist things about the native population and not seeing them as equals. We guess that backfired for this particular earlier American when the natives got their revenge for his comment about suggesting that they eat grass.