The Guardian absolutely is capitalist (neoliberal, even). Just go check back on their campaign against Corbyn (a leftwinger who won the Labour Party leadership from the New Labpour neoliberals some years ago) which included such memorable pieces of slander like calling a Jewish Holocaust Survivor an anti-semite because of him in a conference about Palestine comparing some of the actions of the government of Israel with those of the Nazis, this done in order to slander Corbyn by association since he was in the same panel in that conference.
Also you can merely go back a few months to see how The Guardian supported Israel well into their Genocide (though they seem to have stop doing it quite as eagerly in the last few months).
Last but not least they very openly support in British elections the Liberal Democrats (who are neoliberals) and the New Labour faction of the Labour Party (also neoliberals) and very often have pro-privatisation articles on UK subjects and are never for bringing things back into public ownership even when privatisation has failed miserable to give better services or lower prices.
I lived in Britain for over a decade and read The Guardian for most of it, so maybe The Guardian’s political slant is clearer for those familiar with British Politics.
I do agree on The Intercept and Democracy Now! though.
Can’t really speak for the others with any knowledge.
By that definition all “Industrial Associations” would not be capitalist.
Personally I would be wary of telling people they should trust the words of the spokespersons of most of them.
There are more than one way in which the elites and near-elites organise to advance their interests and IMHO The Guardian is very much The Voice Of The English Upper Middle Class.