Why Chiranjeevi didn't acknowledge Rajamouli?

Chiranjeevi is extremely proud of his son Ram Charan, who received praise from Hollywood director James Cameron for his performance in the period blockbuster RRR directed by SS Rajamouli. 

Sharing a video of the Avatar maker lauding Ram’s acting chops, the megastar wrote, “Sir James Cameron, an acknowledgement of his character in RRR from a global icon and cinematic genius like you is no less than an Oscar itself. It is a great honour for Ram Charan. As a father, I feel proud of how far he has come. Your compliment is a blessing for his future endeavours.”

Although there is nothing wrong with his post, some netizens are surprised that Chiranjeevi did not mention Rajamouli, and are wondering why.