“Yeh could’ve died!” sobbed Hagrid. “An’ don’ say the name!”
“VOLDEMORT!” Harry bellowed, and Hagrid was so shocked, he stopped crying. “I’ve met him and I’m calling him by his name. Please cheer up, Hagrid, we saved the Stone, it’s gone, he can’t use it. Have a Chocolate Frog, I’ve got loads…”
(Harry Potter and the Sorcerer's Stone)
“Do not use I’ll [instead of “I am doing”] for something you decided before.” (Essential Grammar in Use).
Consulting this, ‘I’m calling’ implies he’s already decided he would call You-Kow-Who by his name. Am I right?