Some collectors have large budgets and can pretty much buy what they like, whilst others have much less. If I don’t have vast cash reserves but I’d still like a really nice vintage watch, then my only option is to put in lots of hours to hunt out a bargain. If everytime I find something it gets posted for all to see, then they're always going to end up in the hands of the wealthy guy. I think if someone spends the time to gather knowledge and track down a potential auction bargain, then they deserve to have a shot at it.
Now in this case I know Goodwill gets so much attention that this was never going to be a bargain, so posting it here isn’t really a problem. But obscure listings should, in my opinion, be kept away from public threads. The times I’ve found potential deals that didn’t interest me I’ve always notified members by PM.