Why did Quran say, "May Allah destroy them" if it's from Allah?

Some Christians (including an individual named Christian Prince) cite a verse which say : > The Jews say, "Ezra is the son of Allah "; and the Christians say, "The Messiah is the son of Allah." That is their statement from their mouths; they imitate the saying of those who disbelieved [before them]. **May Allah destroy them**; how are they deluded? > > Surah Tawbah (9) : 30 They claim that Quran is man-made fabricated book. If it were from God, then why would God say, "May Allah destroy them"? Why didn't it say, "May Allah guide them"? And they also say : > If this is Allah speaking then it is saying, "May Allah destroy them" to who? > > If Allah is talking then he will not say, "May **Allah** destroy them" > > Here Allah praying to who? > > Why say, "May God curse you, May God.....whatever etc. That's mean I'm asking God. So obviously I'm not God. And this is exactly what's happening here. So this is how they claim that Quran is not from God. "If it were from God, God is praying to who?"- This is the main point of their argument.