In my opinion: On-line postings tend to bring out the worst in many people for some reason. Some times, because we can't see the facial expression or hear the tone of voice, the posting becomes negative even when not intended that way. The fact that we've now gotten to where some don't even use words, they've gone back to the per-literate days of pictographs (emojis and the like), is a major problem. They can't take the time to give a complete, unhurried answer while "keeping a civil tongue" in their heads. E-mail and postings tend to be done in a manner not consistent with proper written correspondence; they seem to encourage errors of grammar, spelling, usage and a lack of politeness. The writers appear to have not made it past 2nd or 3rd grade English class. However, I've been in the computer industry for 50 years and can state that people displaying all the negatives you mention have been behaving in those ways for at least as long as I've been involved. In fact even longer. My father started with these beasts in 1934 (Electronic Accounting Machines) and told of unpleasant, mean spirited, uncooperative, and unsharing people even then. I fully second your request for civil, cooperative behavior by those in all areas of computing.
Charles Wolfe C. Wolfe Software Engineering