There are some famous critical debates: Is there irony in Moll Flanders? Did Chaucer get bored and give up or did he never actually plan to write two stories for each pilgrim? Did Lady MacBeth fake her faint? (Yes - she was in her night clothes not her corset.) To these I would like to add, Starship Troopers: Fascist manifesto or the most deadpan satire ever written?

Either way it is necessary to work out what is wrong with the society portrayed in the novel and also where the faults in the moral "logic" presented lie. First up - brainwashing: all societies to some extent attempt to "instill their values" in (i.e. brainwash) their youth but setting up History and Moral Philosophy lessons in schools is a clear step too far. (A bit like Citizenship classes or flag worship.)

Second: The axiom: It's harder to argue with the logic than the premise - if the axioms are false any logical results derived from them may also be false. In this case the axioms appear to be: No statement of morality that goes against natural law is valid. Survival of the fittest is a natural law. Hence humans have no moral obligation to any other species.
I prefer: One's moral standards are not tested until they conflict with self interest or indifference. No species or individual has intrinsic moral superiority over another. This means humans are morally responsible to every other species - an opposite conclusion.

It's a scary book, in the way that some political fiction is scary - 1984, Brave New World, Darkness at Noon - but I just can't quite figure out if Heinlein was serious or satirical. It's an interesting excercise to compare and contrast Heinlein's "democracy" with the society of the ancient Spartan state.