Last thing I'll say on this, since this thread is for discussing the horrible new kit
My post was simply aiming to answer your hypothetical question. I'm not saying whether you should or should not be offended.
Now that you mention it though, I do disagree on the reason for being offended.
There is a line between banter and insult. Good friends can insult eachother in terrible ways without it actually being discriminating or offensive. For instance, I have a gay friend that I've known for 20 years whom I sometimes tell to stop being a fag about things. He doesn't care since he knows I don't actually mean what I'm saying. I would, however, never ever dream of saying something like this to someone I don't know very well. Now there's no visible line saying when it's okay to say something like this. This is where the fact that we're not robots come into play. There's a time and place for saying offensive things and it's up to you to figure out what that time and place is.
The joke in this thread, to me, is obviously light hearted banter and not meant to defame Nigeria as a nation or people. It should be taken in the same way that jokes about Livepool fans shagging there sister should be taken, as banter. That is ofcourse just my opinion. If you take offense by said joke, that's completely up to you, as it should be, since you're Nigerian and I'm not. I do take offense however, when someone tells me that simply questioning whether something is racist automatically makes me a racist or an insensitive prick who doesn't understand what racism means.