The point is that you are using the sort of race card name calling to harangue someone else. Do you give other people a hard time when they refer to white Americans as "gringos", which is a definite pejorative? Or are pejoratives only objectionable to you when applied to ethnicities other than white anglo-saxon protestants?
The previous poster might have used an objectionable ethnic/national stereotype, but it has nothing to do with 'race'.
In any event, who are you to set yourself up as the posting cop? If you think a post is out of bounds, complain to the management.
So you think in the big picture "taco bender" isn't racist, huh? Well if we're going to play games, fine, it's not racist if there's no such race, but it's an insult of a particularly low sort revealing a vulgar prejudice among it's speakers. That better?