Growing is work. Hippies (while they were hippies; most changed with time) generally were not well suited for and not interested in work. Between that and few if any real hippies being around any more, that's a major factor why they aren't visible among the grow community.
Many decades ago (70s), when there were still real 'hippies,' I and my peers (righteous local dealers, now would be growers) looked down on them. We called them 'pies.' Good people, good values, good consumers, etc. But they worked at spacing around all day and avoided doing anything gainful or constructive (even dealing); many were multi(any/all all the time)-drug users, abusers and/or burn outs; while we put in time and did the work and took risks to keep their supply lines open. The other major group (at least among those in their 20s at the time) was the political/activist types, and they also looked down on the 'pies.'