You know how stereotyping works? Nazi yellow press "Der Stuermer" was perfect in this.
The guy from the other country might have a long nose (even "Farang" means "long nose"), he might be from a middle east country, and so he falls into the stereotype of an "unwanted foreigner".
I am German by passport. You have any idea how often in Thailand I heard Germans yell "Auslaender raus!" ("foreigners out!")? And it's very easy for them to point at someone's nose like the Nazis did in their aforementioned propaganda leaflet.
That IS racism, nothing less.