Honestly, the population of helpful posters is quite small on SDN. It is the same people answering questions again, and again. Without these people, SDN would be a useless, hot mess.
Unfortunately, even these helpful posters patience wears thin.
Eventually, helpfulness ... gives way to annoyance ... gives way to confusion of why people ask the same stupid crap without doing their own research, after all we are only talking about our careers ... finally, the end result is anger , quelled by humorous mockery .
Edit: Also, sometimes people need to learn just how clueless they really are. See the "funny quote..." thread to see the kind of people that need this type of therapy.