What is the wisdom behind using the word "what" (ما) instead of "who" (مَن) in His, the Almighty's, saying: "Nor are you worshippers of what I worship" (وَلَا أَنْتُمْ عَابِدُونَ مَا أَعْبُدُ)?

Al-Qurtubi drew attention to the fact that the phrasing "what I worship" (ما أعبد) instead of "who I worship" (مَنْ أعبد) was chosen to be paralleled by: "nor will I worship what you worship" (ولا أنا عابد ما عبدتم), which refers to idols and effigies, for which "what" (ما) is appropriate. Thus, the former was made to conform to the latter so that the statements would be symmetrical. He also mentioned that "what" (ما) can sometimes refer to a rational being.