Dr. Phil and the girl's family are only concerned about the young man being Muslim because of the "ownership" a Muslim husband has of his wife and children. There is nothing in the show alluding to racial reasons (he is a native in the Palestinian region) tthat should be considered. The main concern is in regard to Abdullah's Faith/Religion: If she marries him, even in the U.S., his religious right will be to not only verbally, but also physically abuse her. If she has children by him born in his country his right is to keep their children. He can divorce her and send her away without her children. He can also kill his wife if he believes he has religious reasons to do so. He can "make" her stay in his country if she is his wife, and keep her from ever seeing her family again. He can also verbally and physically abuse his children, as a Muslim father, without repercussion, if they live in a Muslim country.
The other concern, nearly as great as the first, is that he has lied to her many times already, and verbally abused her in a most unconsionable way, and she is still not dissuaded. That's a true sign of immaturity: She is not yet ready to make such a life altering decision as marriage.