These discussions go beyond sports and history but to the core of what is good instruction. Good instruction leads to the students thinking for themselves by providing not one right answer but alternatives (a some what constructivist approach).
When we design instruction it is difficult, even in using a design team, to have a design that is bias free. We would expect design teams to reflect the culture they are part of. That makes instructional design difficult because different viewpoints are excluded. For example, when we talk about the bias in the PBS version of the Civil War, such a product would have avoided a Northern bias if a effort was made to include those with a Southern view in the design team. Judging from what I have seen of the PBS special and know of the Southern view of the War for Southern Independence this did not occur.
In designing bias free (as much as that is possible) we need to go outside of the organization doing the design to get other views of the same subject. I have not see this happening much.