Well... BRD considered DDR an illegal occupation whose decisions never took place. For example in the ID cards people born in Karl-Marx-Stadt suddenly said they are born in Chemnitz, because the reunified Germany considered that the city had never legally changed its name.

So, if we take that interpretation, then the 1972 should not be mentioned at all, because it was not done by a legitimate state apparatus but was more like a wild murder instead. This, if we take the BRD view to the situation. This has the nice effect of censoring a bad deed DDR did.

We could of course also claim that the last execution in BRD took place in 1972. But, ehm... Does that really make more sense than just letting all reunified countries be shown in their pre-reunification form so that the deeds of murderous regimes won't get whitewashed?