It's partly strategic. The presence of a moderation comment like that in a thread often seems to evoke higher-quality comments. I'd bet that it such had an effect in this case—the thread improved almost immediately—but who knows.

You're right that I should have written something longer and not in haste. But I'm a bit surprised by the strong reaction to that one; it's atypical. Perhaps to some readers it felt like a disparagement of their own view on religion—which of course it was not.