The parent comment isn't saying "his writing style is bad, and that makes his points bad." It is saying "His points are bad, and the issues with his poor writing style seem to mirror the issues with the points he makes".

You can say that the parent comment doesn't explain why his points are bad, but that has been already discussed to death elsewhere in the thread. So it doesn't seem necessary to copypaste all of that in here, just to make a point about his writing style issues alone.