Well, I'm with you that libertarianism is an impractical and harmful idea, most right-leaning positions are. This does not make it far off from our center, though, when the vast majority of things we interact with in the US already are privatized. Many prisons and schools, businesses, land, etc etc. All in the private sector. So, an ideology that wants privatization of what little we have left, like say, the post office, is not a particularly extreme position for our culture. A far more extreme position would be wanting to do away with our voting and implementing an authoritarian government, as Trump seems to want.
So, there actually is no such thing as some grand, objective scale, no matter what scale you use, attitudes can shift over time and different positions can be adopted or dropped by different points on the scale due to changing technologies, attitudes and situations. The most important thing is that the scale is consistently applied, and provides useful information to the audience. I would argue that the most useful information is provided when the scale is balanced between the various positions that its audience is familiar with. So, again, since its an American organization doing work for an American audience, I think it behoves them to remain accurate to American perceptions.
It should not be trying to change anyone's mind, or change how they view the world, simply scale everything that's out there in a way its audience can find approachable and understandable. It's not intended to be a reform mechanism, but a service to the culture as the culture exists. This is not whitewashing anymore than the US itself is very whitewashed. But again, it's not MBFC's job to fix us, that's what education is for, not news media or fact/bias checking. It is not an education tool.