That was the rationale when the EU killed South Stream - a proposed pipeline from Russia through the Black Sea and south Europe. Some of the countries involved had already made large investments and had great hopes for the pipeline which would have generated transit fees.
Germany's push for Nord Stream 2 - a more or less direct pipeline from Russia - today feels self-serving and hypocritical. It looks like Germany is abandoning its obligations while smaller and less wealthy countries had paid the price.
Also Nord Stream 2 would make Germany more dependent on Russia gas.
At the same time US wants to have EU and Germany on their side in fight agains China + sell resources to EU. Germany on the other side does not like "being controlled" and has some attraction to Russia. There are thoughts that Germany may want to make an allience with Russia to weaken US influence on EU.
I belive it is just a surface of what is happenning. And it is all related to "peace/war" questions, who are allies to whom, global market shares, etc.
It is not just some "stupid decision", there are lots of issues hidden under the hood. And more such decisions to come in the nearest future I belive.
Being German myself, I don't think it has so much to do with being controlled or not, but the difference between several powers having some degree of influence vs. one having it all. Russia and the USA are certainly two very big players in world politics, and Germany already seems to have plenty of co-dependence with the United States.
I don't mean to say Nord Stream 2 is necessarily a good thing, but I do believe that some of the powers involved don't seek this balance as much as just to isolate Russia.
From ukrainian point of view Germany seems to forget about risks of not isolating Russia after Russia annexed territories and invaded several countries. WW2 did begin some kind of similarly as I understand: countries were seeking for "balance" and didn not want to make any rough decisions which could influence their economics in a "bad" way. The result was not very good.
I understand that every country has interests. But in this very case we see that Germany is already buying russian gas through ukrainian gas system without any issues besides risks intriduced by Russia itself. So Nord Stream 2 is more about relationships and not the gas or economics alone.
At the moment we see Article 11 and 13 approved as a consequence. And it is just the beginning.
For the same reasons New York might care how Alaska gets its energy. Climate change concerns. Concerns that a fellow voting union member is building critical economic and energy ties with an authoritarian regime. (More selfishly, perhaps, because New York wants to sell them its own energy.)
For Germany, the alternative currently seems to be coal, which is one of the reasons I find this somewhat annoying. If it was a matter of "Nord Stream 2 or wind energy" I'd say "fuck that Russian gas, let's go green!" But alas, that's not what this is about.
See #Controvery