Mexican residents of texas were known as

the completion of the erie canal spurred the first great westward movement of american settlers, gave access to the rich land and resources west of the appalachians and made new york the preeminent commercial city in the united states.

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.