More like “Act Of Stupidity’’. Hitler and the German General Staff were just to slow to realize how fast the panzers had advanced. But when the British were trapped on the beaches some generals wanted to finish them off but Hitler did have a bit of a soft spot for England in only that he felt the two peoples had the same blood and the same world view in many ways and he felt he might be able to get them to ‘’listen to reason’’ and capitulate. In the end he let Fatso Goering talk him into believing the Luftwaffe could finish them off. As always the Fat Man was talking out his ass. Thank goodness for history’s sake.
That’s only part of the story. The German military at Dunkirk was stretched to the limit. It’s planes, troops, and tanks were worn out. German supply lines were stretched. Their pressure on the Allied forces wasn’t the whole package but it was all they could muster without an all in effort.