Right. You can say its hyperbole or "locker room talk" but in situations like this, it's very clear that a large part of the financial sector is _absolutely sincere_ when they look at retail investors as what they literally call "dumb money", "dumb flow".
“Dumb money” is a particularly poor bit of jargon but as it’s used in finance it doesn’t really mean that the finance sector thinks a person is a rube or stupid.
It really means you think an order doesn’t imply any directionality in the order book. Most orders don’t! Most orders happen because of things outside of the markets (I’ve retired, I’m rebalancing my portfolio, my kid is going to school, I got paid so I’m buying into my retirement fund).
Those orders are not indicators that the market is going to move. This is in contrast to a hedge fund unrolling their position. That act will impact the market.
So for instance while Melvin was taking a bath closing out their shorts they were “smart”. But my index fund sell that made me money was “dumb”.