He was getting his way until now, then he fucked with a living God
The thing is that Kousuke doesn't want to outright kill people, much less the innocent civilians, also, this punishment might look lenient but it might be more cruel because two things will probably happen:
1 - people will know the king and the church utterly fucked, what are the chances the people will rise and do a purge?
2 - if Kousuke decided to destroy the kingdom that was it, but as it was said without a blessing the country is doomed to a slow death, no crops, no hunting, monsters attacking
Kousuke is arguably being reasonable, it's like with the previous idiots who messed with him, the angels made clear to everyone they fucked up and the civilians took the matter in their hands, so the people responsible gets punished and the innocent civilians don't get hurt cause they're smarter than their leaders
Although we don't know what will happen after the purge cause the civilians will still have no church and no blessing, living in that country wil not be nice for a few years or decades until the gods decide to bless them again
In short, instead of a quick death they're going to have a long time of hardships, it's not flashy but it'll send message to everyone to not fuck up with Kousuke without needing to nuke everyone