Dunkirk

Curious programme as it seems to almost deliberately and consciously write the Merchant Navy out of the evacuation of the BEF from Dunkirk. Even when what is clearly a Merchant ship is being attacked by Stukas, in contemporary black and white film, the narrator refers to Royal Navy destroyers! When Merchant ships are referred to they are almost invariably called personnel ships or supply ships, almost never Merchant ships. The only actual reference to a Merchant ship is where one is on fire and a group of Royal Navy people go onboard to fight the fire. Even then there don't seem to be any Merchant Navy people present. Is this a deliberate omission, or one based on ignorance?