Because Putin (and everybody else the world) knows that Germany is erpressbar (blackmailable, open to blackmail).

Just like the current US-Amerika government of… whoever is actually running the government at the moment.
Why Germany was key to prisoner swap deal with Russia – The German government’s decision to release a convicted Russian killer serving a life sentence for murdering an exiled Chechen in Berlin in 2019 was crucial for the prisoner swap between Russia and the West…
The main figure in the swap, which involved several countries, was Vadim Krasikov, a Russian convicted of killing a former Chechen militant in Berlin in 2019.
A clear message to future blackmailers: The German government lets a convicted murderer go free after two years in prison, just like that, somebody who bumped off one of Putin’s critics right here in Berlin’s Tiergarten, in broad daylight.



