It pops up all the time, it’s a waste of time and I’m sure it has been used countless of times to discard some piece of information. It doesn’t add up anything productive to the comments, people who comment don’t even say anything they actually think they just “did you know that MBFC says this so it has to be truth?” I could go on but I think you get the idea.
There are definitely more axis that could be added but the center isn’t unbiased. The left and right tend to be pretty biased. Plenty in the center is too. Where are you seeing the center labeled as unbiased?
The word “center” implies that it’s less biased/unbiased to the majority of people. It’s what average people see as a “safe” source and allows them to read it uncritically. Media literacy is not as widespread as you think it as, as demonstrated with your handling of this subject. Why are you so obtuse about it?
You can make much sharper criticism than that, because MBFC at sometimes suggests and other times says outright that the center is the least biased (see davel’s comment).