You are right, we should just walk away. There are several heavy hitters here that would agree with you. The problem, however, is that it isn't easy for some of us to do that. We are passionate about what we do and we try very hard to help. It could be an OP that just wants the answer to a problem/question getting frustrated or it could be a language barrier. But some of us, still want to reach out help where we can.

Also, for each person we help, it makes up for the several rude ones we deal with. Seeing the light bulb turn on when someone figures out what was wrong and how to fix it makes the dificult times worth it.