The argument goes - These disorders are incredibly taxing for both the individuals who suffer these conditions and for their family, friends and colleagues. There is real suffering and pain, and alleviating this pain, and potentially preventing it through germ-line edits could eradicate these conditions for ever (glossing over the incredible ethical concerns there)
At the same time, these conditions _can_ provide incredible gifts to both the individual and society as a whole. History is littered with famous artists, scientists, etc., who have all made important and unique contributions to the human experience. Would they have been able to do these things without their condition? In curing the disease, are we missing these non-linear thought patterns that are common with these disorders? And what cost does that have for society?