There are words that I know from this quiz that I would never use in real life or in my writings. I’m not sure why. That’s the active vocabulary distinction.
For sure there is a bit of selection bias with hackernews users. Not saying we are all geniuses, but I strongly believe we are, at least, more educated than your average Joe
You are almost always going to find people with above average reading and writing skills on an online forum - especially one with such "curated" audience and spartan UI.
Maybe "few words" means your larger vocabulary lets you use a single word to represent a concept that someone else would need several words to say. But the conversation ends up longer when the other person asks you to define the obscure word you just used.
"May I compartmentalise? I hate to, but may I? may I?"
"Hold the newsreader's nose squarely, waiter, or friendly milk will countermand my trousers"
"...saying the same weary things time after weary time: I love you. Don't go in there. Get out. You have no right to say that. Stop that. Why should I. That hurt. Help. Marjorie is dead"