This is correct, abyssnote should also be fine for writing to system, but you don't want to be flashing it in cwm from an affected kernel. It would be ideal if you flashed ANY unaffected root kernel using Odin before flashing a ROM in recovery. I believe it is okay for a ROM to include an affected kernel, too, so long as you don't do very intensive writing to the system partition while using it, but you would need to flash an unaffected kernel in desktop Odin again before flashing something else in recovery.
Although I think the reason most devs refrain from using it is because it doesn't maintain root on ICS ?
Can anybody confirm or deny this please?