If you look at his piano works, they are heavily influenced by Liszt. See Ce Qu’a Vu Le Vent d’Ouest, which clearly states his influence and admiration. Other works pay close attention to Chopin’s pianism. (Most obviously, his études.)

This person clearly has not done his music history homework.

It’s not that I’m questioning Debussy’s seminal importance. I just don’t want someone falsely claiming he came out of nowhere.