One reason WW2 holds such a prominent place in the British consciousness (particularly Boomers) is that there's not many wars where Brits can rightly claim to have been 'the good guys'
That's something to be proud of, but not complacent about.
And that's exactly what leads to bad faith actors (looking at you Francois, Farage and Widdicombe) holding Dunkirk up as if it's some kind of trophy to aim for.