Such writers don't understand what magic is. It isn't sparks shooting from the ends of your fingers and gills growing out of your neck. Magic can include those things, but that's not all magic is.
Aleister Crowley's definition of magic: "the Science and Art of causing Change to occur in conformity with Will."
To break that down even more, Crowley said, "Every intentional act is a magickal* act."
So guess what? Every time you sit down at your computer with the intention of writing, you commit a magical act.
To those who say writing is not magical because it's mundane, you still misunderstand. Magic is mundane. It's sticking your tongue out to catch snowflakes, closing your eyes to feel the sun on your face, and jumping through mud puddles to feel them splash.
There's nothing more magical than creation.
*magick/magickal was often a spelling used by Crowley to differentiate between illusionists and magicians