The online forums are perfect cages for the exhibition of mental imbalance. There is so much meanness, pettiness, insult, and defensiveness. How did so many teachers and singers become so nasty? There is so much pain and fear evident in these places.
Getting good training, pursuing gigs, recruiting students, solving vocal issues, reconciling with failure, are all very difficult and happen all the time. There is so much pain out there, which feeds fear, which feeds bad behavior.
When someone is mean, try to remember that they are hurting. Calling them on it in a calm and factual manner is appropriate and might help them, if they are ready to hear. Even if they aren’t ready to wake up or help themselves, it will help others to know that there are people who believe in the best in people and expect it from others.
Responding to assholiness with the same can feel good and get you wittiness or toughness points, but in the end, those are not worth having.