Top 10 lists can be misleading. If there are fewer popular right-leaning news sources, then all the right-leaning audience will be concentrated there, pushing them into the top 10, while the left's audience is diluted.

Like splitting the vote, or how Muhammed (and alternative spellings) is the most popular baby name in the UK: https://www.independent.co.uk/news/uk/home-news/muhammed-rea...

You would have to look at the total story popularity, not just the top 10, to make any kind of conclusion.