It is bias if your "factual reality" over-exaggerates the "facts" for the "bad guys" and under-exaggerates / completely neglects to report on the "good guys"
But to put it with John Steward, what if reality itself has a left leaning bias?
What if left leaning people have empirically broader empathy [0] which could imply that right leaning people have in tendency worse personalities. I guess you would attest yet another biased article here.