Never heard of this quote per se; there is dust attacks, and dust.
Will assume it means smallest unit, or very small amount of crypto for example, 1 Satoshi
– 8 decimal places.
Because of the way exchanges work with partial fills you might be left with “dust”.
It’s too small to trade, because it’s below the minimum trading amount, or too small to move between two wallets
due to transaction fees exceeding the value
of the dust.