It is totally unfair. If you can't reply to a request, better you keep quiet than hail insults to a person you don't know. Perhaps he may be a lebanese just like e46M3 or Brazilian just like Terramax who happened to be in Nigeria. Or do all nationals who go to Nigeria are just like Nigerians.
Nigerians are great people and like any other place in this world there are criminals who are dealt with in a court of law. Have a just day.