If you read my original post I did say that traumatic experiences can go either way - it can push people towards God just as easily as it can push them away
At the time of WW1 & WW2 the majority of British people were Christians who attended Church or Chapel on a regular basis. They went to war believing it to be a worthy cause not to mindlessly kill people. Many were very young, raised on the Old Testament as much as the new and firmly believing that God was 'all powerful', he could produce plagues to kill the enemies of the righteous , divide the waters to allow for Moses to flee............they must have felt very abandoned out there when none of that happened
My own father who was raised in a deeply religious family where the Churches and Chapels were the focal point of village life and had been for generations never set foot in one again after the war other than what he called social events like weddings etc because he felt that the things the Church had taught him were misleading and led him to expect too much.
There is a view on God - that we are all here to do the best we can with what we are given, that God interferes in no way at all, he doesn't make good things or bad things happen but what he does give us is the courage & strength to cope with things when they do go wrong.
Aside from wars, which tend to have significant and lasting affects on populations for understandable reason including vegetarianism, it would appear that during the same years (WWI forward) the UK became increasingly socialistic. Having a rather long history of battles and invasions, the UK was no stranger to "war" prior to WWI. I will stop there b/c UK history would be (or most likely is) your strong suit, not mine.