Stephen Miller's grandparents were asylum seekers. [View all]

They fled anti-Jewish persecution in Belarus, where armed guards rode through the streets looking to kill Jews. They arrived in New York with $8 in their pockets and zero legal immigration papers.

This info is verified on Snopes. https://www.snopes.com/fact-check/stephen-miller-descendant-asylum-seekers-fled-anti-semitic-violence/

I'm no psychologist, but there's likely some kind of residual psychological trauma that got passed down that he's acting out....