You are making the false case that these people attending protest and deranged concerts only dress as such for these events, when the case is that THIS IS THEIR NORMAL DRESS.
All of them? At best the counterculture represented a tiny sliver of the population and many of them were what was called "weekend hippies" who had regular jobs with regular dress codes during the week and only "flew their freak flag" on weekends.
Yes they were influential in affecting fashion and dress for the broader culture. But I don't think that was nearly as much a matter of morality than simply the fact that the rest of the culture looked at them and (as several posters have pointed out up-thread) decided to start dressing comfortably. We ought to be careful not to equate morality with uncomfortable dress. By the same token, we certainly cannot equate morality with comfortable attire either.