I'm trying to understand why the bias would be a cause for concern in this case. What consequence could it have on the reading of an article that is tag-lined a

I'm trying to understand why the bias would be a cause for concern in this case. What consequence could it have on the reading of an article that is tag-lined as "[One Side] is a rebel without a pause..." which seems to indicate some bias immediately to me. Is there any person who can write without bias? I don't know anything about journalism, I'm just trying to understand the concern in this case (and in general). To what degree can we really expect reporters to be unbiased? (Another question for you: What examples do we have of completely unbiased reporting?)