In answering this question, we need to refer back to some earlier responses, in which I pointed out that the famous "Christmas Truce" was almost entirely a phenomenon that occurred between British and German forces, for example:
and
The reasons why the soldiers of these two nations felt able to fraternise, while the Germans and the French, or the Germans and the Belgians, broadly, did not were complex but certainly one of the most important was that, in December 1914, Britain had not been invaded (as had Belgium and France) nor yet been exposed to the full force of "atrocities" such as unrestricted submarine warfare. Moreover, while suffering very significant losses, these were at this stage largely restricted to the ranks of the pre-war professional army, not to the civilian "new armies" that would be raised from 1915 on.
What all this meant for the people at home was that in Britain, uniquely, a large proportion of the general public was still not personally invested in the war, in the sense of having sons and brothers risking their lives at the front, and the war itself was still something that might credibly be over relatively soon. It was too early in the conflict for people to appreciate that this was a war that might drag on for years and cost many millions of lives.
This fed in to the response one sees to news of the truce on the home front. Several factors need to be appreciated:
• There were pretty much no "official news" reports of the truce. Rather, news reached the papers in the form of letters sent home by participants, which were passed on to (mostly local) newspapers by the families who received them, often couched as rather wondrous curiosities. This meant there was relatively little in the way of official comment or editorialising on the truce. The letters home portrayed what had happened as a strange, welcome, seasonal anomaly, but certainly something that was temporary and also, often, as something that was already over. There were often comments to the effect that the realities of war would soon reassert themselves.
• All the letters home necessarily reported only what the writers had seen and heard for themselves, so the general impression given was of very local truces between "opposite numbers" - not some general cessation of hostilities all along the line.
• Similarly, the news took some time to reach the home front. The earliest news reports and letters were published at the very end of December and many appeared in early January. So, by the time the public at home were aware of the truce, the "shooting war" had already recommenced. It was easy to see it as an almost literally miraculous, but fundamentally minor and exceptional, aspect of the war. At no time was there any suggestion that the truce might spread, or become permanent, nor that it was in any sense a rebellion by ordinary soldiers against the horrors of war in general.
Taken together, then, and from the perspective of those on the home front, there was no reason to fear that participation in the truce was any evidence of weakness; and while, clearly, there was plenty of "hate" felt for the Germans by the British, and vice versa – not least because of propaganda-fuelled reports of atrocities in Belgium – such sentiments had not yet reached the sort of pitch they would later in the war. There are comments, in diaries and letters written at Christmas 1915, that by that stage things had "gone a bit far" for the troops at the front to want to fraternise with their enemies, but such feelings were not nearly so widespread after only four months of conflict, in December 1914.
You'll note from the above that studies of the Christmas Truce almost invariably focus on British evidence and British public opinion. It would be very interesting to see comparative studies that also took in German evidence, but I would expect there to be significant differences in the findings of such enquiries because ...
• The German army was a conscript one and there was national service, meaning that by end end of 1914, when all reserves had been raised, the German army was far more of a citizen one than the British army was, and hence there was more investment in the war on the part of the general public on the home front. I'd hypothesise this might mean a less significant tendency to see the war as something happening far away that might still have romantic and chivalrous elements to it, especially as...
• Germany had been the aggressor and was occupying enemy territory, rather than fighting to free territory that had been invaded. (This was not, of course, how things were generally presented to the German public, so this factor probably had at best a rather limited impact.)
• Germany press censorship was much stricter than the equivalent censorship in Britain, to the point that it was "all-embracing". This may help explain why most of the German sources I have seen for the truce are regimental war diaries, whereas most of the British sources are letters to the press, though it's also possible there's still much work to do on studying the German press.
Sources
Malcolm Brown and Shirley Seaton, Christmas Truce: The Western Front, December 1914
Alan Cleaver, Not a shot was fired: Letters from the Christmas Truce 1914
Marc Ferro et al, Meeting in No Man's Land: Christmas 1914 and Fraternization in the Great War
David Welch, Germany and Propaganda in World War I: Pacifism, Mobilization and Total War