France has more than it's fair share sociopolitical and racial tensions in the past few years.
That they are slightly less happy than the surrounding nations is understandable.
And that is a reasonable response to the question "what the fuck are the French so unhappy about," and the statement implicitly acknowledges that the French are indeed less happy than would be expected absent such an explanation.
And the most notable manifestations of trouble in France, the recent riots, didn't occur until after this map was produced. It's also not like other Western European nations are completely devoid of all sociopolitical, racial, and violence issues...
To say that they are unhappy when they are actually above average is a bit of a misinterpretation.
I'm so glad that we went through this oh-so-valuable exercise in parsing semantics instead of just understanding that the obvious implication is that France is
relatively unhappy