Respect for a flag.
The captain, a Dutch national, reminisced about his own experience when he was my age, and when he was indentured as an apprentice to a British shipping company during the First World War.
When his ship berthed in New York he, along with his fellow British apprentices, went to the Apprentices Club (originally established by Charles Dickens in the 19th century). He was told that it was a requisite procedure to wipe and stamp his muddy boots on a German flag placed as a doormat at the threshold.
Since his own nation was neutral, albeit he was sharing the dangers of his shipmates aboard a British ship from predatory U-boats, he found himself placed in a considerable dilemma.
He could only make his excuses, pleading an urgent need to be elsewhere in order to avoid defiling the national emblem of a people with which his country had no quarrel.
As we frequently see on TV news bulletins the burning and defiling of national flags are a substitute for vengeance against the nations those flags represent, therefore, the defiling of the Welsh 'Draig Goch' as described in your article is not a matter which should be ignored, regardless of whether it was done with malice or otherwise.
GWILYM L G THOMAS