Yes, as far as I know I made the whole thing up. There are programs at shelters which teach the homeless and recently homeless job interview skills and sometimes a trade. But I don't know of anything involving salesmen.

The 'Among what they teach' part was constructed more by translating objections through the analogy than by any significant reference to the reality of salesmanship. I do not think you can glean too much information about salesmanship from the comment in question.