Because he has a hero complex without any nuance or subtley. He's the cliche Lawful Good Paladin.
If it makes you feel better about his character, he comedically suffers for it in the after stories.
I'm surprised anyone is looking for serious consequences in a series where the holy chick has brass knuckles with "Holy Doom" written on them. And is referred to as such by everyone else.
I mean it's the same type of comedy as "Mongo only pawn in game of life".
Hero: I shot you!
Villain: Nuh uh, I had my barrier up!
Hero: You didn't say you had a barrier until after I shot you. You're out!
Villain: Nuh uh!
Hero: Uh huh!
proceeds to slap fight
It was certainly implied when it took over all the other kaiju and #8 was all, "We've always been at war with this specific kaiju" flashback.
The second half of this series certainly went off the rails real quick.
To add on to that, The rock itself isn't super heated from the friction of entering the atmosphere. So ya, really big splash seems on point. I'd put it on the level of a giant glacier breaking free.
He needs to find a better fence. There's a lot of rare expensive materials going into making arguably less money. All so he can avoid attention I assume.