I wouldn't be too quick to condemn the bike shop owner. He too was dealing with other peoples mistakes. Sounds like he was very gradually taking the least potentially destructive steps to free the post. Nobody likes to pour corrosives into a seat tube. Most folks are squeamish about taking a plumbers wrench to a post and torquing the living daylights out of a properly aligned frame! Might have been a case of fear that he'd successfully remove the post, but crack the frame tubes in the process.
Still sounds like he's got an interesting shop -- which one was that again?
Regards,
Carlo Carr
New Orleans