I might come back and expand on this but the reason is more that Germany is a vassal of the US, and the time has come to make that painfully clear.

Postwar West Germany developed on a combination of US cash infusion and migrant workers from poorer countries, primarily Italy and then Turkiye. The BRD needed to be upheld as a beacon of capitalism in contrast to the socialist DDR just to the east. With the annexation of the DDR there was a cheap and easy way for capital to expand yet again, staving off the worst of neoliberalism in the west for a time. Cheap Russian energy has fueled industry since then as well. Now it's time for the managers of the hegemony to split Europe and Asia, for a united Eurasia would be too powerful. Thus Russia and Germany must be severed economically.

It's not that the postwar bailouts were too generous, but that propping up Germany was economically valuable to the US, at least until the last fifteen years or so. It was then that they realized the new capitalist Russia would not be a vassal to the US, and put into motion their plan to destabilize it. Germany is a victim in this, albeit due to its comprador government a willing one.

For more analysis and thoughts on this topic Michael Hudson is really invaluable, both his books and regular articles and interviews on current events.