Why was conscription unethical in Germany during WWI?

Conscription occurs anytime a government imposes military enrollment on its citizenry. Conscription was a common practice for European nations during World War I, and Germany's system can be taken as a model. Men were drafted when they turned 20 and served for two years; they went into the reserves thereafter, with decreasing likelihood of being called up as they aged.
The benefits of such a system were exercised by the Germans themselves. They had a militarized population ready, as well as a large pool of recently trained reserves. As such, the German army was able to swell from eight hundred thousand to over 3.5 million in a 12-day period in August 1914. Impressive efficiency, to say the least.
Many question the ethics of German conscription on a variety of grounds. First, Germany's intentions in forming a military were expansionist, colonialist, and motivated by social Darwinism. As a result, the conscription is criticized by political thinkers and social justice advocates alike. Further, unlike the British, the Germans had no legal conduit for conscientious objectors. Others contend that conscription was unethical because it discriminated against women. Still yet, some hold that financial limitations prevented the military from drafting 100% of the eligible population, providing room for prejudicial military determination.
https://www.bl.uk/world-war-one/articles/recruitment-conscripts-and-volunteers