Oh good lord, the utter majority of the Left Party today weren't even alive in the GDR period (and of those that were, a good bunch got yeeted to the BSW). And on top of that, all the other parties have gobbled up their East German Blockparteien as well and we don't label them collaborators either, nor do we call the CDU and especially CSU a Nazi party despite many former NSDAP members ending up there post WW2 (or a ton of them forming the AfD a decade ago).

Obviously after 36 years many people of Die Linke were not alive when the wall fell. But it’s still the same party as the SED, just a different name.

The CDU and the CSU have nothing to do with the NSDAP.

At some point in time in Germany 30% of the population were either part of the NSDAP or the Nazi Army. Luckily most of them were not war criminals and move on with their lives. And yes, some of them ended in the CDU/CSU but also of the SED/Die Linke.

Just to give you an example, around 10-15% of the DDR state officials had held NSDAP membership pre-1945.

Does that make the DDR a successor of the Nazi Regime? Obviously not. The same about the CDU/CSU.

But Die Linke is still the same party as the SED. Same organization, which just voted themselves into different names.