I've never read Ebert's reviews before. Did he always sound like a condescending douchebag when talking about things he disagreed with? But reviewing video games as a medium without even trying one sounds a bit like criticizing literature without reading a book.
End of the day, art is subjective. And video games have been around for, what, 40 years? If you don't think they qualify as art yet, give them a few more centuries...