Yes, its a quantum epigenetic resonance effect. I can sell you some crystals to treat it, if you like.

It’s a joke that the rise in left handedness correlated to the time period of the war. It’s just pointing out a spurious correlation, and falsely equating the two.

Either you just whooshed really hard, or I am by posting this. I genuinely can’t tell if this is sarcasm.

I think that poster is wrong by attributing it all to the war, but what they're implying with trauma is physical trauma causing the non-functioning, or requiring the amputation, of a right-handed person's right hand. Probably a lot more acceptable to be left-handed when your right one has been blown off and all.