we want to be an emotionally supportive group for people who make a badge of honor out of being socially and professionally inept
Unwarranted assumption. If this interview was as bad as I think it might have been, it is not at all inept to cut it short. It's done all the time here in the US; interviewers cut short day-long interviews when they realize the candidate is not going to work out. There's nothing wrong with politely abdicating.
"I don't think we're a great mutual fit. I will keep my ears open for you in case any of my friends would be a good fit for your position."
That is a perfect thing to say while you're cutting it short.
Unwarranted assumption. If this interview was as bad as I think it might have been, it is not at all inept to cut it short. It's done all the time here in the US; interviewers cut short day-long interviews when they realize the candidate is not going to work out. There's nothing wrong with politely abdicating.
"I don't think we're a great mutual fit. I will keep my ears open for you in case any of my friends would be a good fit for your position."
That is a perfect thing to say while you're cutting it short.