You were asked which war was won purely by defence to which you answered "WWII"
I never said it was won purely by defense.
Only that you might want to take a closer look at its various subcampaigns -- several of which (including the Winter War, the Battle of Britain -- and the entire Eastern Front campaign) were effectively fought and won entirely defensively. (Yes, the latter campaign eventually moved outside of the USSR's borders; but that was long after it was effectively won while still well inside the defender's territory).
Plenty of other wars have been won entirely defensively as well of course (including nearly all the colonial and neocolonial campaigns that were eventually lost, up through Vietnam and both of the recent Afghanistan occupations). Oh, and somebody mentioned that other major war in Europe in the same century as well.
I only picked WW 2 because it's everbody's favorite. As for it being, as a whole, simply defensive -- sorry, but that wasn't what I meant to say. All apologies.
You were asked which war was won purely by defence
to which you answered "WWII"
when you were asked about D-day, you said that "Nearly every war has both offensive and defensive phases."
which as you'll agree is not "won purely by defence".
thus, I put it to you again, that your original statement was bollocks.