It's completely impossible for them to not think of this problem in a black and white fashion or to imagine that the east could have produced anything good, regardless of which of the systems was better overall. Women's rights don't matter, queer rights don't matter, full employment and social security don't matter, all they can see is stasi and lack of bananas.
When faced with empirical facts and statistics (often even ones collected by west germany) wessis panic and start comparing a state that had a political persecution death toll of 140 and never persecuted anyone based on ethnicity or immutable characteristics to a state that genocided 6 million jews across europe (Bordering holocaust relativization tbh).
Meanwhile people that actually lived in the GDR mostly see both its positive and negative aspects. An annexation in which all of their positive accomplishments were discarded, their economy was dismantled and illegally sold off to western investors for joke prices (in most cases just done to kill off competition) and the legacy of their system was reduced to exclusively its worst aspects was framed as a "unification", and yet the west is surprised at the lack of enthusiasm for the liberal democratic system in the east.
