> I must completely misunderstand the purpose of the German system of conscription

Conscription would be compulsory enlistment for service. That is, the government selects you for the work and you have no choice but to do it. It’s a rarely used practice almost exclusively employed for military service.

The topic of this petition is civic service. Civic service is volunteer work done for the good of the community. Civic service work needs to have a direct public benefit, not simply claiming that it makes you personally better educated.