Three points I want to make:
1. Germany is relatively more reluctant to the oversea adventures unlike the other two major EU powers, namely UK and France. UK was always active in oversea intervention and destabilizing of countries around Europe, from Iraq to Syria. France was reluctant during Jacques Chirac's presidency, invasion of Iraq is a good example. Unfortunately, his successor Nicolas Sarkozy was trigger happy, Libya and Syria. His opposition counterpart François Hollande was trigger happy too. So I would think Germany was more of passively being dragged into the actions due to being a member of EU and NATO. The German reluctance can also be seen in her milder tone in Ukrainian crisis.
2. The fact that both François Hollande and Nicolas Sarkozy are active in getting into the wars even they are from opposite political camps, the fact that Nicolas Sarkozy turned his party's position 180 degrees from his predecessor Jacques Chirac and the fact that the German SDP and green party (usually would be expected to be anti-war) were warmongers all indicate that politicians in a western democracy do not have a long term strategy or political principle. Their decision follows the mood of the populace who is then lead by the sensational news articles and bloody photos from media which is then controlled by somebody. There is no way the individual politician can or will or able to do anything against the tide, that is political suicidal. They are only the speaker or executor of that somebody, the populace is just brainwashed by the somebody through the media.
3. One person can be rational, but the behavior of a group of rational people may not be rational, the behavior of a mix of rational and irrational people is totally irrational.
So, I would blame less the individual politicians, but blame both the institution for its faulty design and the population for their irrational and emotional behavior.
