It's pretty deep.
When a false religious leader turns the people against you, letting them go ahead and martyr you certainly is the Christian thing to do.
Plus, look at The Stand.
On the other hand, Roland doesn't even go back in time far enough to actually revisit Tull. It would be much easier to tell if his salvation is what the DT cycle is really about if it had turned out that he was never in fact needed to protect reality, instead of it turning out that he was.