The reason the IBOR has problems is that you can't arbitrarily take away the right for certain websites to declare themselves Conservative or Liberal, and then disallow disruptive content. For instance you cannot force FR to allow DU content or vise versa. People with a moral and political viewpoint should be able to come together on a site where it is inexplicably stated that such a site is established for that viewpoint.
Think of it like this. If a site is working to elect President Trump And they are constantly Being disrupted by those who Hate Trump and love Hillary. Then how can that site get anything done? It will be just be constant fighting.
I understand what you are saying. I think that many would feel better about the IBOR if they felt that sites such as the ones I mentioned would be protected. But yes I agree that there is a real problem with sites like FaceBook and Twitter. They try to claim that they are balanced when they are not.