One of the costs of being open is that you are subject to trolling. I think it's important to realize that while trolls are very vocal, they do not represent the entire user community.
A user that asks for a specific feature, and is understanding and supportive when it's politely explained that the feature is difficult to implement or lower priority compared to other things is absolutely a positive contributor. A suggestion of a feature is a useful thing even with nothing else and even if you've heard it a dozen times before.
On the other hand, trolls tend to repeatedly complain about the lack of a feature even after being the reasoning is explained. Trolls like to begin sentences with "If you really want to defeat Microsoft...". They do stupid things like reopen bug reports 100 times after it's politely explained that the issue is not in fact a bug.
To survive in an open environment, you have to be able to filter trolls. There's nothing wrong with adding filtering rules to your mail clients to send any mail from an individual that behaves like this to /dev/null. It's the only way to maintain sanity IMHO.