And after Austria declared war, Germany invaded Belgium, in accordance with a very detailed mobilization plan arranged long in advance. I'm glad to know that you are more loyal to Kaiser Wilhelm than your own nation, if indeed you are an American. A humanitarian intervention on the side of the allies was eminently justified, as it was in World War II. Germany was the clear aggressor and disruptor of the peace.
LOL, this is like when the Democrats accused the Bush administration of planning to attack Iraq prior to 9/11 because there were "plans" for doing so somewhere in a vault. Every government maintains battle plans for virtually any continency - the militaries of the world hire people that do very little besides create strategies and plans to be filed and likely never used.
Actually, Germany did nothing until Russia mobilized against them FIRST, just like France mobilized against Germany FIRST (truth be known it was the French ambassador who was pushing the Russians to attack Austria in the first place).
The simple fact is that the problems were totally between Austria and Servia and no one else. It was Russia, prodded on by the French, who stuck their nose in and started to spread the hostilities. When Russia, unprovoked, moved against Austria, Germany was bound to defend their ally. An ally, by the way, whose war against Serbia was totally justified. The Germans gave the French ample opportunity to declare their neutrality and keep peace in the West -they failed to do so. The French were looking for any opportunity to get Alsace-Lorraine back from Germany after the spanking they got in 1870; just as Britain was looking for any opportunity to remove German economic/colonial competition.
Frankly, I see nothing "humanitarian" about American fat cats getting rich selling arms, ammunition and all manner of supplies to the British while thousands of Germans are starving to death, all the while pretending to be "neutral". I see no sense in condemning Germany for invading Belgium when before the war, Wilson had invaded numerous countries in Latin America for the sake of American business interests. The warring powers were all on the verge of exhaustion by the time America declared war anyway, it could not have gone on much longer regardless of what the US did. All Wilson accomplished was to give the Allies overpowering force in the final days to inflict on the Central Powers the most atrocious, humiliating and ultimately dangerous peace terms they could force out.