Zhao Hai said this to Ma Rulong because he wanted to see Ma Rulong's reaction. If Ma Rulong was extremely shocked, it would mean that he had guessed correctly. If Ma Rulong was extremely confused, it would mean that he had guessed wrongly or Ma Rulong didn't know about this.
In the end, Zhao Hai got the answer he wanted. He had guessed it right!
Zhao Hai looked at Ma Rulong's shocked expression and laughed bitterly. It seemed like the higher-ups of the realm of machine arrays had indeed suppressed the cultivators many times. This was probably not news to the higher-ups of the realm of machine arrays. Otherwise, Ma Rulong would not have such an expression.
