Well that’s because it’s a short sentence and the challenge list is long. Artist generally seek to challenge 3 things right off the bat: the medium (can this be done here), themselves (can I actually pull this off), and the audience (can you handle this). Now within the realm of audience challenging there are many more possibilities. You can challenge their view of themselves, their world, or art. Also you can challenge their ability to simply digest the art, there’s a lot of amazing art that comes from the “sit down, shut up, hang on” school.
How can you understand the truth if you’re not challenged? Truth isn’t easy, truth is tough, truth almost always comes with admissions of error and failings. You can’t serve the mind with a challenge, it’s like a muscle, you don’t make a muscle stronger by only staying within its comfortable stress zone, you have to challenge it, try to do stuff you’re not entirely sure it can do. Same with your mind.
If you want art to serve your mind and help you understand Truth you MUST consume art that challenges you. By avoiding challenge you flee from Truth.
Must? Not sure. Art can challenge you without "seducing" you "into conniving in the violation, because we have permitted our fantasies to accept what we know to be revolting".
By avoiding challenge you flee from Truth.
Life's filled with enough challenges, and one simply cannot avoid Truth indefinitely. Further, one needn't elevate the process of tempting or being tempted to "art" in order to be properly challenged or to encounter the truth.