Don't ignore them, call them out and embarrass them, shame them. This is how people like them think they get power by belittling others. Name and shame them and if the others are cheating by lying where they are from (why would you need to do that) report them. I am not on here that long but there is a vast amount of pompous arrogant pricks on here who constantly ruin a round for you because they don't know how to behave.
The problem with the world today is that too many people "leave it" and "ignore it". I say don't "leave it" and "ignore it", meet it head on and fight fire with fire as you said yourself if they spoke like that in real life they would not be on here because they would be getting fed through tubes.