It may be a little distasteful to some making a profit from this stuff, but Hilary Stone doesn't appear to ask huge prices for his stuff - less than they would go for on ebay in most cases. He also has a massive amount of knowledge weh it comes to older bikes, he has identified frames in a number of cases when no-one else could.
However, I have never intentionally made money from cycle jumble purchases (never to my recollection), I buy the parts for my own use, and would hope that others do the same keeping the prices much more reasonable than ebay. I have noticed the prices climbing at cyclejumbles for frames especially though.
Old Ned - it's never nice to have that happen, but at least you can take the moral high ground. If you weren't willing to sell it in any other way then you did what was right, they will have to live with their concience (if any) for inflating the price.
The sad truth is that traders are often needed to save old bikes (or cars, or what have you) as they can save far more of them than us as hobbyists, should we begrudge them a living, or the occasional business practice that grates us - as we are not doing it for the money.
There are a few traders though (one recently banned here springs to mind) that none of the above applies to, they should be banned from buying bikes!!