This is a cultural difference. In America you value freedom of speech above many other rights, including privacy. In Germany, it is the other way around - Germans value privacy greatly, but do not necessarily think everyone should always be allowed to speak their mind. For example, you can go to jail for denying the holocaust happened... but on the other hand Privacy International acknowledges german privacy safeguards while naming the united states an endemic surveillance society. (source. It seems even Germany is slipping on PI's scales these days...)
They are private facts. The people who hold that information have always been, and will always be, contractually and legally obliged to keep those facts private.
The identity of the murderers isn't just a fact, it's a public fact, part of the public record, established in a public trial.
The main facts remain the same, only the names will be expunged from public access. I would say this is because, once freed, criminals regain a lot of their rights to privacy.
The question is whether government has the right to retroactively rewrite public databases, public records, and public facts. The only possible answer is a resounding "no". Fascist states, dictatorships, and communist states rewrite history; democracies do not.
Oh, you can't just denounce everyone who doesn't share to the your particular viewpoint of an ideal democracy as fascist! Different cultures have different needs. Both viewpoints are trying to achieve an ideal but falling short as realistic governments are bound to.
Anyway, it's not altering history, it's expunging names from the public record to protect people. It's not like they're writing someone else's name into the history books.
This is a tough question.
No, it really isn't
It's just that your particular value system only permits one possible answer, but not everyone shares that system precisely. Disagree if you must, but at the very least you have to agree that in Germany, the german people should be allowed to make their laws as they see fit. Now, American law disagrees with German law. How then do you approach such an international thing as wikipedia? You don't think this is a tough question? The obvious answers all leave a lot to be desired.