Your flag would have contributed, along with others, to lowering the rank of the story and also to the [flagged] marker getting put on it. I don't think flagging was appropriate in this case—the app seems as on-topic as any other, and the fact that the material is religious shouldn't make a difference, although religion is of course a divisive topic and most religious-themed submissions tend to get this treatment from some users.

From an HN moderation point of view, religious tolerance follows from the value of intellectual curiosity, which is what we're optimizing for (https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...). Not all religious posts are on topic, of course (most aren't), but they are when there's overlap with intellectual curiosity, the same as with other divisive themes (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...), and when that's the case, tolerance is paramount.

Religious tolerance has been a prime principle of intellectual culture for many centuries. If you zoom out to a historical perspective, it's clear that it's in all our interests to practice it, regardless of what our religious or irreligious views may be. We don't have to hold the same views to respect each other, and the art of interesting discourse with people who hold different views is something we should all cultivate, assuming that we have the intellectual curiosity that the HN guidelines speak of.

From a different angle: the problem with mobile apps as Show HNs is that they're not easy to try out (https://news.ycombinator.com/showhn.html) without going through the rigamarole of installing them. But that's a problem with the entire category, and as long as we haven't disallowed them (which we're not going to), this submission seems as valid as any other.