Why "mysterious ways" don't matter.

[Esquilax]

I don't believe the mysterious ways speaks to his motivation so much as it suggests that he has a justification for his acts which would be acceptable if known.

Hence my third example: a justification that's present but not explained is indistinguishable to a third party from one that doesn't exist, and we certainly aren't obligated to completely suspend judgment because the accused refuses to give his justification.

Especially not when, as christians who use this excuse so aptly demonstrate, it's used as an unthinking, catch-all nullification of argument, sans any kind of demonstration that such a justification even exists. If you're going to just use "mysterious ways" as an answer to every contention right away, it's not as if you're actually thinking through available evidence and coming to the conclusion that an unknown but valid justification is most likely. You're just using it to shut down dissent.