Online news is an "inferior good"

My professor said something today that really made me think -- yes, I do that sometimes. She called online news an "inferior good." She explained that the more income a person has, the more likely they are to go elsewhere for their news -- not online, and she has research to support this. People like to go online because it's free, obviously, but if you have money, you're more likely to go elsewhere, and probably pay for it (i.e. newspaper, magazine, cable). What's not said here is that the same information is online.

I don't know why this research finding bothers me.