I lurk a lot as well for the same reason. Many forums of all topics (probably most of them out there) have similar problems. I think (just my opinion) that it happens for a few reasons:
-people read their own emotion into the words
-people tend to feel more brave when they are not face to
face and feel somewhat anonymous
-it can be frustrating when people ask the same questions without trying
the search function first and people continually take info from the loyal site users and then disappear
-there are many schools of thought on every topic and when people are passionate about something and have been doing something the same way for years that works for them they are often not open to new ideas or ways of doing things.
Just my two cents
