Hippie? That novel has often been characterized as semi-fascist, and it has pre-Anime mechas and alien bug colonies that essentially get genocided, I'm not sure what book you were "reading".
I suspect Heinlein gets categorized all over the map (from "hippie" to "fascist") because critics looking at only one of his books don't realize that he's using science fiction to explore (but not necessarily fully endorse) different sociopolitical and cultural arrangements. He constructs a Sparta-style government of the military elect which gets mistaken for fascism in Starship Troopers. He describes a free-love new religious movement in Stranger in a Strange Land. He engineers a libertarian-anarchist[1] revolution in The Moon is a Harsh Mistress. Heinlein portrayed none of these systems as perfect and seemed, to my eyes, to be exploring their implications in a scifi setting rather than plugging for any one of them.
[1]: Libertarian used here in an American context, though some members of the lunar revolution in the novel are monarchists, syndicalists, and anarchists as well.
