I have been working on https://bifocalnews.com -- a news feed that scrapes political subreddits. This allows for a democracy-driven news feed with explicit bias stated for each article. Started this site for myself after realizing I had nowhere to go to get reliable political perspectives from both sides on popular topics, and I do not like that major news corporations get to choose what is on the front page.
I like how at first it just shows the headlines/articles. Then, if you want, you can toggle the "show bias" switch.
Have you thought about an option to gamifying it a little bit by letting the user guess which direction the headline leans? And then revealing the direction and the news source.
For example, when the "enable bias guessing" switch is toggled, there's a slider that appears on the bottom of the headline. Or, simpler, just two buttons that say left, right. You can guess all of the headlines on the whole page, then reveal and see how you did.
I like the idea of getting user feedback and gamifying the site a bit. It also might be interesting to take the bias guess results and show where on the spectrum of left to right site users think a headline falls. Thanks for the suggestion!