Jim Kalb has written a piece for Crisis Magazine about the 1960s. He takes a generous approach to the 60s radicals, arguing that their reaction to a materialistic culture was understandable but that their solutions made things worse.
It's written to Jim Kalb's usual high standard and is well worth reading. I'm not sure, though, to what extent the 60s radicals really were motivated by idealism (I'm not old enough to remember that decade).
When I looked into the main figures that Australia contributed to the 60s counterculture (e.g. Richard Neville, Germaine Greer) I found that many of them had been members of the Sydney Push. And the Sydney Push itself was strongly influenced by the left-libertarian philosophy of John Anderson.
Anderson's philosophy was not exactly idealistic. I've written a more detailed account here, but in short he laid the groundwork for some of the beliefs of the 1960s radicals by arguing that there is no morality embedded within reality; that reality can only be understood through a scientific methodology (scientism); and that the only "good" activities were those which were free, critical and creative. This meant that what mattered was not reform but an attitude of opposition.
Anderson also believed that sexual repression was a major means by which freedom was constrained. You were not supposed to have sexual hang-ups (jealousy, attachments etc.).
So the underlying philosophy of the Australian leaders of the 60s flower children was, seemingly, a harshly soulless one from the beginning (but, again, I wasn't there - maybe some of the rank and file were attracted by the idealistic sounding slogans of the movement).