The reviewer has NO conception of genuine citizenship, and most likely could not recite the Bill of Rights without referring to an encyclopedia. The reviewer has a marvelous sense of humor, or is brain-dead. One need only study the course of American society over the past several decades to see the cultural decay Heinlein alluded to. The reviewer is a prime example of the very attitude Heinlein decried.
Many people feel it's because of a softening, more permissive attitude.
Personally, I think a big factor stems from the various sides not appreciating each other. He seems to scrupulously avoid a dualistic notion of one side being better and the other worse. A healthy society, like a healthy body, needs different parts - the muscles can't get along very well without the brain and vice versa. Still, Steve, according to RAH, there must have come a time when mutual 'appreciation' was no longer possible, or else the militaristic status quo in the book would not have existed. Your point about the two extremes is valid.