Earlier quoted context omitted.
> if he limited his responses to “this is a bad idea” or “this isn’t done right” And then people keep wasting his time insisting on a bad idea Cultural differences and all that. A good 'perkele' will be enough to get the point across in most cultures, even if some leave a bit disappointed.
It is easy to filter such people out. Especially if it is email the sole medium of contact.
How long do you stay on the list? And doesn't this assume that every idea that person has is bad? What happens when some good ideas are caught in the net? (And what happens when someone goes off and grabs help to implement the bad idea, because you weren't there anymore to tell them again not to do it that way? Or worse, what if they come around to your point of view, but can no longer reach you?)
Wouldn't it be better to just say no, emphatically, and in a way that is clearly and unambiguously no? (I don't think it absolutely has to be a personal attack, but at least it's not passive-aggressively putting your ideas into a blackhole echo chamber...)