Why Did the Promised Unpopular Spell Become a Forbidden Spell?

This book is also called "Dignified Immortal Emperor, you are actually a low-level magician?" After traveling through time, Ying Changning originally wanted to practice immortality, but he was too weak and had no human rights. Not only was he captured, he was also used as cannon fodder, and he even had to take the blame. Fortunately, I have discovered the special ability to extract and infuse all things. Extract and inject coagulation technology, coagulation technology breaks through the level limit! Extract and inject evaporation, and evaporation breaks through the level limit! No matter what kind of spell it is, Ying Changning can extract it and inject it into his body, allowing them to continuously superimpose and transform. Ever since, the style of painting in the world of immortality has been distorted. "The blood coagulation technique is the most powerful magical technique in the world. It can kill the Immortal Emperor invisibly." "Nonsense, the evaporation technique is the most powerful in the world. You can evaporate an entire sea area with a snap of your fingers. Who can stop it?" "Isn't the Earth Gathering Technique strong? You can bury the Immortal Emperor in the sky and on the earth." "What you are saying is so weak! The most powerful magic in the world is the corruption technique, which can corrupt the world and corrupt the realm forever!" In front of the forum, countless monks were stunned as they watched the several immortal masters arguing endlessly. Aren't these... All low-level spells? How does it sound like a forbidden curse?