For anyone that ever tried to edit Wikipedia, just like anyone who had to live in a 1960s concrete tower block, the idea that something so appalling might need protecting will likely seem crazy.
But the problem with destroying the past – even if it’s a totally abhorent symbol of the past whether slum housing or ideologically driven propaganda – is that if future generations can’t see these failings of the past, then they are bound to repeat them.
Take for example the notorious list from the Wikipedia talk page of “common complaints by sceptics”. It neatly encapsulates every sceptic argument – it’s like a “who’s who” of issues that should be in the article but were barred and replaced by overt propaganda.
And that it stood there for so long signalling to each and every sceptic that the article was clearly and obviously biased – is a testament to how deluded some people can become when they “get power”.
That’s a lesson we all need to learn.

Wikipedia is not a reliable source

That’s the other. The editors argued ad nausea about whether non-academic sources could be allowed in “their” article calling anything not produced by a left-wing academic “unreliable”. But not once did they consider whether Wikipedia itself was reliable or how their bias impacted on the perception of Wikipedia.
We need to maintain these follies from the past – because through such follies we can get into the mindset of our generation and from that there is just a small chance our children will not repeat the same stupid mistakes.

Common complaints by sceptics

To view an explanation to the answer, click the [show] link to the right of the question.