Because this is The Economist?

Further, the harm, if any, of most degrees is to the person who pays for it. People are generally allowed to do stupid things that don't hurt others. But Mintzberg and others argue that the harm caused by MBAs is to the economy, while individual MBA-holders profit. That would be a tragedy-of-the-commons situation, which isn't self-correcting.

MBA's are different than people with degrees in Sociology. They tend to hire other MBA's, and stuff organizations with fellow MBA buddies. They damage things.

IMO, the problem is that these degrees give you the technical tools needed to function as a manager, but fall short in developing leadership skills -- which is bad news when companies automatically place McKinsey alums with top X MBA's in influential positions.

My arts degree has been very practically applicable for doing work in the real world! I'm an employed artist!

They rant on it because far too many people don't think it's a pants-on-head retarded degrees.