Microsoft competes hard to win business. Sometimes its employees may cross the line into unethical behavior. But not in the case of the Nigerian government switching from Mandriva to Windows, declares Microsoft:
Microsoft has a strong relationship with the government in Nigeria and will continue to partner with government and industry to help meet their needs. Microsoft operates its business in accordance both with the laws of the countries in which it operates and with international law.
I'm not surprised and take this at face value. I know from personal experience that Microsoft particularly hates to lose to open source and will give away its software to keep a customer from opting for open source. I'm sure that's what happened here. Is it wrong? Not really. It's not necessarily fair, but it's part of competition.
In fact, I've talked with several open-source companies who tell me that they've been on the cusp of winning deals only to have their proprietary competition discount their license fees to zero to win the deal. Most can't do that for very long without hurting themselves, but it shows just how desperate the proprietary world is to stave off the open-source threat.