You clearly lack reading comprehension. The quoted text is not trying to draw some distinction between "defending" and "celebrating one's accomplishments" and say that the former is bad while the latter is fine. What it does do is point out that the common attack on socialism that accuses actually existing socialist states of being totalitarian hellholes and important historic socialist leaders of being dictators is a load of shit; using a consistent standard to compare them to their contemporaries would reveal that socialism accomplished many wonders starting from extremely difficult conditions and that most "democratic" leaders are far more monstrous than even the nastiest tales cooked up about Stalin and Mao.

Among what I just said and some other things, it makes a point that is very pertinent to this discussion: the characterization of tankies as "uncritically defending authoritarian regimes/dictators" (as asserted by the zine from the OP) and detesting literally all dissent regardless of what the content of that dissent might be (as you asserted) is also a load of shit that depends on treating socialist experiments as radioactive failures that are entirely bad and not worth defending. Tankies are perfectly capable of recognizing and criticizing the mistakes those experiments actually made; the commonly hurled criticisms are torn apart because they are factually wrong and made in bad faith.