Because we now have 20/20 hindsight that Russia is an evil actor and would not reform. Therefore Germany should have spent the previous 10 years getting off Russian gas (leave nuclear power plants open is one obvious example)
An experienced politician should know better.
Like every other (sovereign) state.
Self-interest also implies that it works for Russia. It very clearly hasn’t, and could undo the regime.
The level of violence and aggression is like some mid/late 20th century empire building BS.
It's the US that took out international law and beat it to death in sight of the entire world.
define "works".
there's a big divide in the World on this war, it could be considered a victory for Putin, he made friends fight over it, turned allies into adversaries and made enemies even more suspicious of each other. We are at a peak high level of conflict, like we haven't seen in decades.