Has this world always been crazy?

The year 1940, the place Dunkirk in North Western France ...

Very briefly ...

As it becomes more and more obvious that the German army is about to invade Western Europe the British government sends hundreds of thousands of troops across the English Channel to support those of their French Allies.  The Germans attack the Netherlands and Belgium drawing the British and French northwards across the borders to stop the German advance ... those sneaky Germans do the unthinkable and launch a second attack behind the allied armies cutting them off and driving hard to the Channel ports of Calais and Dunkirk.  Amazingly almost 350,000 British, French and Belgian troops are rescued from Dunkirk and transported to England in just about any ship that is available.  To make sure that the evacuation goes ahead the British continue to send fresh reinforcements right up to the last minute including tank and other armoured units.  And what do the French do ... call a Dock Workers strike!!!

Now I know this happened, I have documented evidence of how utterly fed up the tank men were that they had to unload their own vehicles and equipment after arguments with the french workers.  But I just can't find out why they were doing it ...

To that end I have come to my own conclusions and have come up with the following grievances that they may have had:

1. Immigration ... they were worried that with the large influx of British and Belgians and Germans that their jobs might not be secure any more.
2. They were annoyed that the evacuation of the troops was being carried out by non-union members ... a definite no-no!!
3. They were concerned at the levels of noise that the constant bombing and shelling was producing as it broke the unions rules.
4. Or ... and this is probably the most likely ... they hadn't had a strike for a while and thought it was about time they had one.

I would love to know more about what was going on, I really would, but this just seems to be one of those things that has been lost amongst much more important events of the day.  If anyone has more information or knows where I can find it PLEASE let me know.