There are folks that can't stop themselves from arguing even if they can see that their boat is already sinking. It's all about the pride that they can't just let others stomp on together with their egos. You are on an online forum where the arguments are placed and expect that sets of differences are there. One can disagree or agree to any argument but make sure that you're not too harsh just because you are correct or you are trying to someone who's probably not aware of things that you're discussing and trying to argue. I know that there are people trying to make themselves good and correct even if they are out of argument, it's not painful to be corrected and correct someone. But when someone insists that they're totally correct but actually they're not and you're done with it, leave them alone.