Everybody has his/her (I recall only one
her on this forum though...

) own limitations......sometimes people have had a direct experience of the problem in question sometimes they don't have a clue...sometime people are busy and they miss such polls....there are N reasons for this observation....all we can say is that people here try level best to answer all questions they can...
I remember that I made this
observation when I was new on this forum and that may provide some insight to you on this issue.....
Just try to help as many as you can......