I have a couple of observations: firstly, it's interesting that the Guardian is considered to be dead-centre, while most in the UK would say that it's quite on the left. I found that surprising.
Also, I guess this analysis is taken from the perspective of the USA, given the chart on adfontesmedia. The definition of left and right (at least the Overton window) differs somewhat by country, and I feel that should be made clear on your site for global visitors.
On the topic of differences, I spotted Al Jazeera on there and it made me recall that 'Al Jazeera Arabic vs Al Jazeera English' has now become somewhat of a meme, with the former being anything but progressive: https://twitter.com/search?q=al%20jazeera%20arabic%20vs%20al...
That again just makes me think of how news outlets change their reporting depending on the audience. I'm not sure if that changes anything for you though.