In 1856, an antislavery group led by John Brown killed settlers at

Pottawatomie Creek

Explanation:

The Pottawatomie slaughter happened during the evening of May 24 and the morning of May 25, 1856. Utilizing swords, Brown and a band of abolitionist pioneers took from their homes and murdered five "proficient slave trackers and aggressor professional subjugation" pilgrims north of Pottawatomie Creek in Franklin County, Kansas.

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.