I think this is a lot less dangerous than you think. When people throw around terms like "groomer", "nazi", and "abuser" with reckless abandon, labelling someone as "bipolar" hardly compares. Ultimately anyone that agrees with what Kanye is saying will not be swayed by the label, neither will those who disagree with him by the lack thereof.
A lot of the commentary about his mental illness seems to be focused on trying to find an explanation for why his ideas and positions seem to have radically shifted in the last few years. Honestly, it kind of gives him an "out". If he was not afflicted by some kind of mental illness when he called for "Death con 5", his actions are even more morally suspect.