This is a repeated point made by the writer. The thing that needs to cleared is that Muslims believe that Allah is above the heavens and His knowledge is everywhere.
In this section, the writer makes the same claim of miracles not existing today:
Each Prophet brought miracles with him. Just claiming Prophethood was simply not enough. People back then were not as advanced as us in terms of man-made technology and their knowledge was also not as vast as that of today. Miracles were a common thing those days. Today is the era of science and technology and one doesn’t need miracles like those to realize the truth. According to University of Chicago, 300-400 people are becoming Muslim every single day in the USA alone. They do not need to see dead being raised to convince themselves. These people are just reading the Quran and getting amazed at its beauty. Back then, people would have questioned some amazing scientific miracles in the Quran and therefore miracles were a common thing back then.
Again (!) the writer dislikes the fact that disbelievers in God will be punished. His not believing in Islam is a different thing but to say that those who reject God, abuse Him and mock Him are not worthy of punishment is totally absurd!