It scales. Privately owned community newspapers might have a bias, but if there’s one in every town with 1,000 people, then exponentially that increases the amount of different agendas of each of those private entities, and they can sort of cover each other’s weaknesses. It’s the concentration and consolidation that’s the issue.
Of course, private industry inherently wants to merge and consolidate, as is the nature of capitalist competition. So either you continually break up mergers or develop a public community newspapers that are independent of any government - its debatable how independent the BBC or CBC are.