John,
I have been on these forums for only a little over one year now, and have possibly learned a little about forum poster. I could be wrong but I will share my perception so far. I'm sure others have learned more than I ever will.
After the words on ANY subject are read, the meaning is not always taken as it was intended.
Sometimes people innocently don't realize how offensive their own words.
Maybe, some people are upset with their own lives and lash out through the anonymity of the internet similar to the way some people exhibit road rage.
In the same half full, half empty scenario; when reading a post some people try to look it as negative when they could just as easily read it as positive.
But I do believe that people are good, they just do and say things sometime that aren’t so good.
 I think a good rule of thumb is: When posting people should; keep it clean, keep it civil, keep it truthful, stay on topic, be responsible, share your knowledge and treat people the way you want to be treated.