It is even better than that, a dust attack is when your wallet receives a very small amount of sats to an **already used** address. That's why the Wasabi dust attack threshold doesn't prevent you from receiving very small amount of sats but from receiving very small amount of sats to addresses that have already been used.
Someone can only dust a know/ used addresses, never seen unused addresses get dusted. Btw the threshold features covers the entire addresses ( Used and unused )