Why is there racism in Islam, even though it is a true religion and the religion of Allah, as some Arabs boast of their Arab identity and mistreat non-Arabs, which contradicts Allah’s saying: "Indeed, the most noble of you in the sight of Allah is the most righteous of you," and the Prophet’s (peace be upon him) saying: "There is no superiority for an Arab over a non-Arab except by piety"? And is the hadith "Whoever insults the Arabs, then those are the polytheists" authentic?

You must repent from the statement, "I will leave this religion if it is racist," because the intention to disbelieve, or to make it conditional, is immediate disbelief. Allah is self-sufficient, in no need of anyone. It is stated in a Hadith Qudsi: "If the first and the last of you, and your humans and your jinn, were all as pious as the most pious heart among you, that would not increase My dominion in anything." Islam is innocent of the racism of those who claim to belong to it. Islam has condemned racism and boasting about ancestry.

As for Allah not having created all people as Arabs, there is profound wisdom in this. He created them as nations and tribes so that they may come to know one another, and the most honored among them in the sight of Allah are the most righteous. A Muslim submits to Allah's wisdom in what He has created and commanded.

The hadith "Whoever curses the Arabs; those are the polytheists" is a Munkar (denounced) and Mawdu' (fabricated) hadith. The preference given to Arabs is because the Prophet, peace and blessings be upon him, was from among them, and most of the Companions and Imams were from among them, not simply because of their lineage or because they are superior in the sight of Allah to others.