Lord Rama is the great avatar and stands as the testimony of being the normal person and gone through the ordeals of a human being as we confront the life with challenges. Probably Bengalis have the habit of mispronouncing the word and it is not Joy but Jai and it is not Sea but Sia. And coming to the observance of calling just Jai Shri Ram and not Jai Sia Ram, please note that the word Sri or shri refers to Sita Devi and and she was always given the honor of being first and then added Ram to the words so that it becomes Jai Shri Ram. Moreover Lord Rama always carry Sita in esteem and she is located in his heart and even without referring her, she is given the befitting place to be with the Lord. And therefore whether you simply call Rama, or Jai Sri Ram or Jai Shree Ram, the glory and the pride goes to both of them.
'Idhuvum Kadandhu Pogum "
Even this challenging situation would ease