Hopefully, one day, somebody will answer as to why so many (particularly American) Deadheads are right wing. I suspect it's that RW/Utilitarian crossover point, but what do I know...
Its an interesting question.
There are multiple enclaves within that community that encompasse the whole spectrum of values and lifestyles. If you've witnessed an indordinate amount of right leaning Deadheads, you might have tapped into one of those enclaves due to a shared interest that has nothing to do with politics at all.
Example: If you happened to have been a tape trader - MANY traders are boarding school alumni. In the late 70s through the early '80s, trading became a big thing within the boarding school networks. They, in turn, introduced the Dead to their friends back home further building the enclave. Most of these folks did not become hippies, but retained their upper middle class Republican leaning identities.