That's absurd. 419/Yahoo-Yahoo and corruption are a big problem there. That makes Nigeria poorer, not jokes.
If that's true, how about you simply make your comment minus the joke?
Also worth noting that those scams mostly come from the United States now, not Nigeria.
http://www.sfgate.com/crime/article/U-S-Internet-fraud-at-al...
http://www.economist.com/blogs/economist-explains/2013/05/ec...
People are too sensitive these days. Especially people who get self-righteously offended on behalf of someone else.
Relevant: http://www.huffingtonpost.com/2014/12/01/chris-rock-colleges...
I am Nigerian. Not that it matters.
"So what is scambaiting? Well, put simply, you enter into a dialogue with scammers, simply to waste their time and resources. Whilst you are doing this, you will be helping to keep the scammers away from real potential victims and screwing around with the minds of deserving thieves."
The morality of what is done might be questionable though, especially for 'highly successful' operations that leave the scammer in another country's desert without money. Most just end with a photo of the scammers doing things like wearing a fish on their head.