Everyone has bias; that, I expect. When writing editorials and columns, I expect the journalist to write from their point of view.
Reporting hard news is a different situation. They should be professional enough not to interject their personal, biased commentary.
Part of it is educational indoctrination. Surveys have shown an extreme imbalance of hard "leftists" teaching journalism, so no surprise that the next generation of journalists are even farther "left."
There is no effort to "understand" society, and history in education has become revisionist history, often teaching untruths and manipulated. Even the concept of critical thinking has been redefined.
This is why non-mainstream media has risen to such heights. People no longer trust the mainstream media. Unfortunately, a lot of the non-mainstream media is even worse.
Not sure how that can be solved at this point.