So one says, and so reality says in perspective, and so our interpretation of the lies promulgated by the wall builder says, but do not forget that the official reason for the wall was to keep East Germany from being invaded by fascists from the west.
It is also appropriate, I think, to note that the mayor of Berlin condemned the wall as destroying the prospects of millions, and given that he is not a communist it might suggest that he does indeed understand that its effect was to keep the East Germans from freedom despite its stated intent. It is, after all, possible to lie about why one does what one does. Although the communists were very good at lying, I don't think they invented it, and it seems pretty certain that it did not die out when they did.
It is remotely possible that the mayor of Berlin does know his history.