Why would McAfee block content from Oxfam advertisement?

[David T.]

According to the FTC, representatives of Innovative Marketing posed as representatives of real companies and organizations—including Travelocity, Priceline, and Oxfam International—and purchased advertisements supposedly on their behalf. Those online ads employed an ingenious variant on location-based targeting. They appeared legitimate when viewed from the IP addresses of the ad network's employees, but viewers at other addresses were redirected to fraud sites. More recently, according to a report by the security company Websense, infected advertisements—placed by ad networks that had not thoroughly checked out the clients—have shown up on Gizmodo, TechCrunch, and the website of the New York Times.

McAfee AntiMaleware can be set to block suspicious advertising like those mentioned above including OsFam

Hope this helps...David T.