If you consider the constraint that Last Week Tonight is primarily a comedy show themed around important newsworthy issues rather than an investigative journalism show it's hard to imagine it done any better.
He and Jon Stewart keep (kept in the case of Jon) using this excuse when they get things wrong, but when they get things right they take all the glory they can get. The show(s) have to have some sort of accountability.
For example Couric was just ripped for adding 6 seconds of dead air on a documentary....but that's literally what The Daily Show had been doing for years, making people look like idiots (so it fits their segment narrative). That's all good fun until you realize young people think people like Stewart and Oliver are trustworthy news sources.
I like what they do in many cases, but I despise this excuse that it's "just" a comedy show. Maybe NBC nightly news should just add an in-studio audience that laughs and suddenly they can get away with every screw up.
That's exactly what it is. It's the equivalent of those people on YouTube who assault someone and then say 'it was just a prank!'
I think making fun of someone and trashing their reputation without being super careful to check all the facts first is really nasty and I don't like watching either of their shows.
Edit: I have heard Stewart say "we're not the news" in response to questions like "Do you feel a responsibility to cover every important issue?" where "we're not the news" means they only cover issues they can make funny (an example of something perhaps too sad to make funny is the Flint water crisis)
That doesn't mean I agree with the person they are interviewing, or that that person isn't ignorant...but there is no way you can see their reporting as objective.
https://www.bloomberg.com/view/articles/2014-09-23/don-t-eve...
Jason Jones talks to two hunters, a non-fatal hunter and a fatal hunter, to see what method is better. (4:33)
It's not meant to be an excuse, it's meant to be an accusation. If a comedy show is so much better at news than a news show, that's a major failing on the part of actual news shows.
If he's not going to actually consider the facts, why make jokes about current affairs rather than just totally making things up?
Should we hold these types of shows to a talk show standard or a news standard?
When CBS presented a fabricated military report about George W., they were rightly condemned for presenting false information and presenting it as fact. If, instead, the fabricated document had been shown on John Oliver, would we think it's OK simply because John Oliver is partly comedy?
As with The Daily Show, The Nightly Show, and the (former) Colbert Report, among others, the format is a variation of the format of a mixed news/commentary show of the type that is the staple of the cable news networks, and they all use that format because they are parodies of that kind of show.