> What surprised me is how quickly these kinds of projects get treated as spam across communities, even when there’s no monetization, no ads, and no growth hacks involved. In some places, just mentioning “I built a small ranking tool” seems enough to trigger suspicion or moderation.

Because most places don't want you to post self promotion and leave, that's spammy.

> I’m not trying to promote anything here.

You are, that seems to be your only intention. Your first 2 posts (out of 3) were about promoting your site and now your third post is complaining about unsuccessfully promoting your site.

You promoted your site and then left.

https://news.ycombinator.com/newsguidelines.html

> Please don't use HN primarily for promotion. It's ok to post your own stuff part of the time, but the primary use of the site should be for curiosity.