I've also seen films and documentaries saying the same about Russia. The Bolshevik in Doctor Zhivago mentions peasants rushing to enlist.
Those nations might have had standing armies. But when war broke out in 1914, they needed more men, and a great many eagerly enlisted.
Yes, it does, and indeed many men enlisted all over Europe due to a feeling of patriotic duty, and some of them maybe due to a sense of “adventure”. Grotesque, but true...
We may consider this naive from our point of view, but imho they had no clue what the reality of a fully mechanized war of mass armies was going to be like, since there had not been such a war in Europe before.
However, in the latter years there has been done more research in Germany on the question how people reacted to the outbreak of the war: a few young people were enthusiastic, as I said, but the majority were apprehensive, if not shocked, at the prospect of a major war. This was especially true for farmers; and not just because it was harvest time, after all.
Furthermore, it ought to be remembered that AQOTWF was a novel, and I have no clue how realistic the book was in all of its details.
P. S.: it seemed to me that you had been talking about the size of standing armies of the European nations before the war - the British were the only bigger nation with no national service, iirc, but it came in 1916.
That’s what I had in mind when answering to you; I regret any misunderstanding :-)