Only because...the textbook definition and the colloquial definition differ. I think generally when people say 'fluent' they mean 'native speaker level at reading, writing and speaking language X', whereas fluent actually means you can speak without hesitation on a range of topics.
Just a clarification, not an attack!
Edit: Plus, I wouldn't knock wordlists. I started trying to make wordlists only out of words I had some connection to, but you end up spending an inordinate amount of time making cards, and also then it's tempting to keep interrupting your reading to make new flashcards.
I am 'fluent' in mandarin, and use HSK6 wordlists as a base. I learn a bunch of random words and then suddenly, when I'm reading an article, there's the word I learned a month ago. I don't need to interrupt my reading flow, and the connection has been made. Sometimes at advanced levels, you won't see a word that often, so it's wasteful to see it once, make a flashcard, and then never have another chance to see the word in a real world context for another 6 months.