That wasn't mkempe's point at all. Either you missed it, or you're trying to put words in his/her mouth.

mkempe's point was that there are universal human values. There are universal values for plants, which are different from human values. The "relative" was relative to whether you are a human or a plant. For humans, mkempe was claiming that values are universal.

You can disagree with mkempe if you want. That's fine. But don't misrepresent his/her position.