The dhimmi in Shariah law are the non-Muslims living in a Muslim dominated society. They have half the worth of a Muslim in court, inheritance, legal status. They have to pay an annual fine in a humiliating ritual each year for the right to remain non-Muslim. Don't pay the fine or don't have the money for it, either convert to Islam or be executed, per the Koran.
Routine humiliations per the Koran like not receiving the same greetings, having to keep their faith from ever being seen by Muslims, never allowed to have a taller home or better clothes or interrupt a Muslim. No right to own a weapon or defend your life from a Muslim, so you're always at their mercy. And mosques routinely called for murder of non-Muslims - which you still see today with Muslims riled up on Friday mosque sermons rampaging through Coptic Christian villages in Egypt, killing Christians and Hindus in Pakistan, etc.
Given routine humiliation and depredations, the internalized it. It is an understandable reaction - if you begged harder and longer, you were less likely to be killed in a rampage. If you talked about how horrible you were and how evil your group was, you could get a position of public influence. Think of it as the most outspoken supporter of the Hindu caste system as an Untouchable, doing it to be appointed head of the Untouchables.
Thus it can be a survival trait and personal advantage to internalize and repeat how horrible you are, how bad you are, your group deserves to be on the bottom.