@KamiKira00 They can't punish the other heros for exactly the same reason Naofumi couldn't be executed. The heros are super important and with even a slight punishment it would at best, lower the rep of the country, and at worst, it could start a full-blown war.
The murals in the temple showed what looked like humans, monsters, and other things working together or at least going somewhere together. That's pretty neat.
I really enjoy this series, 1, because it's just plain good, and 2, because the author didn't turn all the important historical figures into hot young men, unlike some other manga.