but at the end of the day these communities I’ve posted to are exactly for this so I don’t see a problem with it

If you were a user with some post history to establish yourself here, who had participated in these communities previously, either as a poster or a commenter, had gotten to know the demographic that resides here, and who had then posted about your own project, you'd have gotten a very different reception (well, maybe not, because of the AI opinions, but you at least wouldn't have gotten shit on for the self-promotion). That's not what you did. You created an account and immediately came to advertise your vibe-coded app. It might be a quality product, but nobody here knows you, you have no history, and you're shilling slop, so that's what we're assuming it is. Nobody's going to touch it.

Also, if you do want to participate here long-term, maybe research the instance you're signing up on and make sure you agree with what they promote, because the instance you choose immediately creates a preconceived perception of you.