If you haven't seen a slant, then those two news agencies are slanted towards things that you already believe. In reality, all news agencies are slanted somehow.

There's no possible way they could cover every single issue from all perspectives, right? So even if you think that they're trying to be as neutral as possible, the stories that they pick and choose to cover tell you what their values are.

And sometimes being neutral actually means you're being slanted, because sometimes the truth isn't in the middle. Sometimes some of actors really are so bad that you need to call them out on their bad actions, at least if you have any morals.