I made no such universal statement. Some people enjoy hard things simply because they are hard. My claim is that this can also result in people thinking some literature is better than it is, because people draw satisfaction from the effort itself.
The point you might be missing is that some people might enjoy hard things not only because they are hard, but because only through their laborious efforts is the true brilliance of the work revealed.
(Edit: re-reading what I wrote earlier I can see how it can be read that way. My bad. )
And for what it's worth, there's plenty of modern-style "hard" novels that I've enjoyed immensely as well, including House of Leaves, Infinite Jest, Shogun, The Pillars of the Earth, and [pick any Neal Stephenson novel published this millennium].