I have never heard a sermon in my life (that I can remember, if I did, it musn't have been very memorable), however I'm pretty sure that there's only a very limited amount of sermons you'd "need" to hear before they start getting repetetive. As in, once you've heard a few, you've heard them all. Literally.
I mean, seriously, there's only so much preaching one can do about the same book for hundreds of years before you literally run out of new things to say.
Regardless, my point is that I actually do learn things, including moral lessons, from the various pieces of entertainment media I so consume with gusto. Wether they are scientific, economic, political, religious, etc... I always learn interesting things from them, more than I ever learned from religious classes at school.
And before anyone says that that's all useless trivia, let me tell you something. One piece of media actually helped me redefine my worldview, my personal philosophies. It made me realize that, things aren't always as black and white as they may initially seem. That things like vengeance aren't just empty, but harmful even. That forgiveness is not just a morally good thing, but can also prevent crime and suffering if someone only has the courage and will to do so. I could speak more in detail, but I'm not going to right now.
What is that wok of fiction you ask? Well, TBH, it's Attack on Titan. Yes, say what you will, about it being overhyped and all that. But it doesn't change the fact that the story and themes really made me think. And that while initially Eren seemed cool for his unyielding hatred and drive for revenge, it actually is a bad thing. Just like him, while I initially supported his characterization, so did I realize that finally seeing the ones he chased get their comeuppance didn't feel satisfying at all.
True justice is trying to prevent further crimes and suffering, not just punish existing ones. At least that's what I started to believe.
What I'm trying to say is, that life changing knowledge can be found anywhere, depending on the person. And considering that DJS is still is hypocritical, hateful self, his endless sermons certainly aren't what he's looking for. If anything, they only make things worse for him by continuously reinforcing his horrible self image and worldview.