Truth or not, newspapers fund themselves by flattering their readers' opinions.
Paper 1, which prints only truthful and legally fact-checked stories about how X is fucking over Y and X is clearly evil, gets a lot of paid subscriptions from people who support Y.
Meanwhile, paper 2 prints only truthful and legally fact-checked stories about how Y is fucking over X and Y is clearly evil, getting a lot of paid subscriptions from people who support X.
The real truth is that X and Y both do good things and bad things, and always take the opportunity to fuck each other over, leaving plenty of factually correct material for the partisan journals, who just don't bother reporting all the skullduggery their "own side" gets up to.
I guess the hope is that, in a healthy media ecosystem, anything important enough to have a constituency gets reported truthfully and legally fact-checked by somebody.
The public are still free to care which truthful things they care about (or want to pay attention to)—and part of the job of politics is still to try to direct attention toward aspects of truth that favor your political aims. But with sufficiently many truth-motivated reporting organs reflecting sufficiently many constituencies, the work of truth-finding gets done.
Paper 1, which prints only truthful and legally fact-checked stories about how X is fucking over Y and X is clearly evil, gets a lot of paid subscriptions from people who support Y.
Meanwhile, paper 2 prints only truthful and legally fact-checked stories about how Y is fucking over X and Y is clearly evil, getting a lot of paid subscriptions from people who support X.
The real truth is that X and Y both do good things and bad things, and always take the opportunity to fuck each other over, leaving plenty of factually correct material for the partisan journals, who just don't bother reporting all the skullduggery their "own side" gets up to.