I think the identity of the character addressing "you" in the lyric changes as the song progresses.
she flips her hair for you...you start to fall... she follows you home but you'd miss livin' alone-- the SINGER is addressing a male rock and roller who attracts female groupies (one of them is who follows him home) and the singer says in so many words "I understand why you won't settle down." Later on that same SHE sends him a message on a piece of paper she somehow manages to tape to his mic stand (presumably after a one-night stand that she wishes would go into something more long term--hence the "regrets.") The groupie writes, in her message, "You (meaning "one"--herself or any other smitten fan) "can't hold the hand of a rock 'n' roll man" because there are just too many competing available females out there for him in his travels. Of course "Joni Mitchell" (the persona in many of her songs in the 70s) desired and achieved the independence and freedom to be as promiscuous as any male rock star. But this song indicates that she was still sensitive to the desire for "security" (if that's the right word--maybe it should be "possession") of the other partner in these brief connections. DAVID LAHM