This reviewer like many of the academic upper-middle class seems to have a tendency to avoid what they regard as an unthinkable solution for our survival: revolution. So in the review of Angus's book he constantly refers to "fossil capitalism", by which he means fossil fueled capitalism. This type of framing, which is typical of other members of this comfortable class like Naomi Klein, and not wanting to offend their capitalist masters from whom they have received so many benefits, suggests that there is another kind of capitalism that is sustainable. Ergo, revolution is off the table, instead we must look to a reform of the system.
Löwy clearly prefers Angus's book to Smith's which simply lays out a very convincing argument that nature and the human-made capitalist system are incompatible. Thus something has to give, and that something is clearly capitalism. But Löwy seems unsatisfied apparently because he expects Smith to provide a recipe for the elimination of capitalism.
Richard Smith’s point is perfectly coherent. The only remark I would make is the absence of mediation. How can we move from the suicidal train of capitalist civilization to an ecosocialist society? This question merits further examination.