There isn’t anything wrong with dissonance, as conflict and discord is a natural part of life and necessary for all positive development and maturation. And in most areas of society, conflict is something we very much want to resolve. But in a great deal of avant-garde art, the goal seems to be to stay in the conflict itself, which to me becomes a way of just inflicting the listeners with our own neurosis. Dissonance and high chromaticism is important to explore; the Modernists were brave to delve into parts of the human psyche that are dark and edgy, but I do think they got somewhat stuck in that. A lot of art pushed audiences away for some time. I think people naturally and instinctively want to experience transcendence, resolution and the feeling of redemption, joy and peace that the resolving of discord can yield.
Here’s his setting of “Ubi Caritas,” which shows him to be most definitely practicing what he’s preaching. Lots of dissonances to be heard, but resolution is the overwhelming “take-away” impression, in my opinion. (That might have something to do with the extraordinary “Breaking Into the Sunlight” moment of the final “Amen.”)