While this Tribeca Festival premiere — which has gone on to play numerous queer film festivals from Frameline to Outfest — runs a bit long and feels narratively rangy, it’s worth celebrating for how joyfully those involved express themselves. “Queer joy,” as Starling points out, isn’t all rainbows: It comes from an often terrorized, even animal state when sexuality is stifled by policy. The South Carolina-born Starling is mounting a local-theater production of “Rocky Horror” with a troupe of thespians — several of the youngest whose parents don’t know their involvement — at the 350-seat Broadway Theater. Other members of the cast are older, and have a more generational tie to what “Rocky Horror” means in queer culture — and why it’s still on drag stages and in repertory theaters to this day. The footage of the actual inaugural “Rocky Horror” performance buckles a bit under draggy asides.