The words clearly are not random. I don't know how the author chose the word bank, but it's not a representative sample. It's all fairly common words and then intentionally silly words that are very long (Hippopotomonstrosesquippedaliophobia), that wouldn't really appear from a random sample as frequently as they do. I tested myself from my own Webster's collegiate dictionary some years ago with actually random words and the results were way off compared to this.