Yes, I understand that. I mean, why don't these censors block the whole wikipedia.org access then?

If they don't want their population to access a Wikipedia topic/article and can't block/determine if someone is accessing it, the easiest thing to do would be just block it right away. So why they won't do it?

(PS: I'm in no way in favor of censorship, I'm just trying to understand such mindset)

If you censor too much people may be pissed. It's much easier to decide "we censor specific articles about specific subjects" than "we censor all of wikipedia". Censoring a popular mainstream webpage may cause too much opposition. Maybe even the politicians who make the decision and their families like to look up things on wikipedia.

Then https will force them to either extreme which I think is a good thing. No option to slowly raise the temperature so the frogs won't jump out of the pot.

But can't they just download the Wikipedia backup, purge the articles they don't like, and redirect the DNS lookup to a local copy?

To the average citizen, it won't look much different than going to actual Wikipedia.

This is feasible, assuming the government is willing to pay for the hosting.

As well as forge an SSL certificate for *.wikipedia.org.

Last time I checked, Wikipedia had HSTS enabled. So trying to forge their DNS without also forging their SSL certificate would be equivalent to total censorship for anybody who has previously visited Wikipedia.

Assuming the government in question has access to a root certificate this should be possible.

Even presuming it is possible, it still raises the cost of censorship. Simply raising that cost is a good thing.

They are currently creating a Wikipedia clone in China so I'm guessing they are allowing wikipedia only on a temporary basis.

Probably because they recognize the utility of Wikipedia.

As with GitHub.