I know what you mean and have some sympathy with your view but I'm guessing it might have been to save the mods having to continually move inappropriate threads to another forum.
Many of the posts in Accidents and Close Calls are not GA related at all, nor yet are they even close to the light end of the GA spectrum but still many might have been posted in Private Flying with its sub-bar of 'LAA/BMAA/BGA/BPA The sheer pleasure of flight'. This way you do get to read about and comment upon them without having to dig them out of one of the many 'Professional' forums.