In the Bhagavad-gita it is always stressed to Krishna by the words aham and mam. Similarly in the Srimad-Bhagavatam the same stress is give from the very beginning - Param satyam, the Supreme Truth. If we divert our attention to worship other demigods, then our faith in Krishna will be flickering. We Gaudiya Vaisnavas, under the guidance of Lord Caitanya, want steady attention for Krishna, not flickering. Therefore, in our line of thoughts and action there is no scope for worshiping any other demigods.
Letter to Ksirodakasayi, 29 January, 1970