It's too bad; a book on what plants might think or what their views might look like - a look which took the project seriously in extrapolating a possible plant civilization and its views and ethics, a colossally ambitious and scientificly-grounded work of SF - could be pretty awesome. But from the sound of that review, it's exactly where Marder falls down.
After contemplating how odd it is that people have a revulsion against weapons which use disease and poison that they don't seem to have against weapons which use momentum and in fact are apt to consider momentum weapons high status, I wondered if there could be sentients with a reversed preference.
I think sentient trees could fill the requirement. IIRC, plants modulate their poisons according to threat level.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.