Wow, awful lot of blows being traded . It feels, at least to me, unnecessary (although who am I to get in the way of a nice healthy debate).
To me, Lichtenstein's work is art. Art that's thoroughly deserving of its place in pop art history. But did he steal from other creators? Of course he did. He made a statement using others work, but he definitely used others work. In the art field it was HE who made the statement, so he received those accolades but in the legal world there's no way that what he did couldn't be construed as a massive violation of copyright. (If not the work-for-hire creator's copyright, then most certainly the publishers).
So yeah, appreciate the pop art of RL (which I do), but acknowledge that he lifted whole images out the wazoo (which I duly acknowledge).
This way Gene can still correctly argue the merits of the work and Chris can correctly argue the outright theft. Win win. Hug it out.