The editor that published Edward Snowden’s revelations was kicked out not long after doing it and the Panama Paper revelations led to no significant prosecutions in Britain and that newspaper went really quiet really fast on that.
I lived and worked in Britain before and after living elsewhere in Europe, so I’m painfully familiar with the politics there (and have other references to compare it to) and sadly the Press is not even close to being the independent 3rd Pillar of Democracy in Britain, as it is (sometimes more, sometimes less) in other countries of Europe. This is because Britain has as First Fast The Post system where the 2 mainstream parties which alternate in government regularly have more than 50% of parliamentarians with little more than 30% of the vote, the monarch actually has some real power and there is a 2nd unelected chamber whose members are either nominated for life of inherit the position from their parents, so you could say it’s far from a proper Democracy and the Press has long been used as a tool to quell or channel away discontent from actually wanting changes to the System in place. It’s not by chance that Britain fell so easilly a very similar kind of Left-Right War In The Moral Plane (aka Identity Politics) that stays well away from things like Wealth Inequality, just like in the US - it keeps the structures of power and wealth in place and unchallenged.
One thing you must be aware about the upper classes in Britain (and than includes almost all journalists and editors at The Guardian except 2, as well as all members of Board) is that they’re all about image management (they literally are brought up to never share their true feelings or present anything but a carefully crafted positive image, and I say this from personal knowledge), so I’m not at all surprised people who haven’t lived over there long enough fall for the posh local smoke and mirrors.
I’m genuinelly shocked that you think partisanship (the cornerstone of Propaganda and the very opposite of Journalistic Integrity) is a good thing in Journalism. I guess you’re from the generation who grew up in the Post-Truth, Crumbling-Democracy Era and have always seen the various Press entities as natural tools used in Political Infighting, rather than as the independent Pillar Of Democracy that’s supposed to keep the Political and Judicial pillars as much as possible honest. Having never known anything but a Press corrupted by Politics in a post-truth environment of propaganda wars, you trully believe that’s what the Press should do (all of which has more than a passing wiff of Orwell’s “1984” to it)
One really has to have completelly lost track of (or never have really dug down enough to get it) the point of Democracy (and hence the rationalle for its architecture) to want the Press to be nothing more than a tool of Politics.