A criminal act is a criminal act, get caught and you should be prosecuted to the full extent of the law, spying is not an excuse for a criminal act. Germany as well as all other countries should actively pursue those involved and prosecute them to the full extent of the law, keeping in mind the death penalty for espionage still applies in the majority of countries. You want to behave in a criminal fashion expect the consequences you deserve, especially keep in mind there is no statute of limitation on espionage.
Where a government wants to pursue espionage via the internet, other countries have the right to pursue reparations via the WTO. Why the world trade organisation, it provides the means of fiscal recovery and of course this relates to the exportation of toxic bits and bytes on commercial import export channels.
Your deceit that "but mommy everyone does it", is just that a very juvenile deceit, every effort should be made to prosecute, recover costs and apply full penalties for criminal activities.
How about this as an extension of your idea. Flying body, quad copter aerial mine, with enhanced glide characteristics and upper surface solar panel, armed by reactive metal batteries with oxide opposing pole, where the oxygen can be released to trigger high speed chain reaction combustion (explode). Released from light aircraft at altitude, capable of ranges of fifty or more kilometres and targeted at specific individuals. Released in flights of three, one to break building skin, another to enter seek primary and a third to confirm and achieve secondaries. Any modern country should be able to manufacture and deploy them and the obvious targets politicians that oppose the desires of the deploying country. So as far as I am concerned, a desirable outcome, politicians who fail to diplomatically strive for peace become the primary targets, so when they take actions that lead to war they are the first to die, giving more sound politicians an opportunity. In the case of the US of course they could be targeted more effectively at corporate boardrooms, to ensure executives strive for peace and not war, else they will become the first victims of it.
Just about any country could deploy them ie Iran vs US oil companies, Russia vs EU Banking Cartels. Most of us would be left out of it as it would only end up targeting those at the top and as a excuse for war very difficult to prove where they come from and really as far as the majority citizens in the targeted nation were concerned there would be real conflict as whether to cheer or frown. So acceptable by your logic or not?