A post with 5 likes is hidden by 1 flag. Or the other way around: A Post flagged by 1 user gets 5 likes, but remains hidden.
What about community moderation?
Are those quoted above claims of fact, questions, or suggestions?
Because, if claims of fact, I think those are incorrect. I do not think a post is hidden by the fact is has gotten 1 flag. In Discourse, post can be hidden by several flags of regular users, and while I’m not sure about that threshold in community.osm.org is currently, I’m quite sure it is bigger than 1.
I also don’t think number of likes has an effect on it (either for hiding, or unhiding)
What about it? (i.e. what exactly do you mean, anything beside auto-hiding post when it gets several flags by regular community members?)
This has already been discussed somewhat at https://community.openstreetmap.org/t/post-hidden-by-community-flags/3367. There, someone linked to https://meta.discourse.org/t/what-happens-when-you-flag-a-post/275 which essentially said “how flagging works may be changed by the people administering a particular site”.
Depending on the trust level of the user performing the flagging, I suspect that that that is possible, and the trust level needed to do that isn’t actually that high. See also https://meta.discourse.org/t/trust-level-permissions-table-inc-moderator-roles/224824. That table suggests that TL1 (anyone who registered 24 hours ago) can do this, but just to be clear again, those appear to be defaults. and may be different here.
Also:
(TL4 is supposedly manual promotion only ?), so unless post above is outdated, I would guess regular (non-*-moderator) user should not be able to hide any post except TL0 (freshly created account less than 24h old), but only increase its flag count (according to the table you posted, and nukeador post above)?
Anyway, I am still unclear about the what exactly is being asked/wanted in this thread? Might be a language barrier 
I could be wrong, but I think what he’s getting at is that if a post has 1 flag, but no likes the system hides it. Which, theoretically, would be comparable to other forums systems where if a post gets a negative like count it is hidden. But conversely if the post that has 1 flag gets 5 likes it still remains hidden. Whereas, with other forums it would be unhidden as being at +4 likes.
The whole thing seems to rest on the idea that a flag on this forum is comparable to a dislike on others. Either way, if you have 1 person who doesn’t like the post, but 5 that do, then the +4 who do should overrule the 1 who doesn’t. At least if it’s weighted. And it really should be. Otherwise your kind of stuck with a first come first serve kind of situation where who ever gets there first can hide a post by flagging it and it can’t be un-hidden no matter other people think it’s perfectly fine. Or to put it another way, why should a negative view overall an infinite amount of positive ones? Like say I post something that gets 9 thumbs up, no one has an issue with at the time, then a few days later someone flags it. What inherently makes that flag more important then the other people’s opinions?
Was late last night: The idea being, if a flagged post gets a certain number of likes, that might un-flag the post, without moderator intervention. If it was flagged off-topic, this would be a strong clue to moderators, to break it out into its own topic. I guess I have seen this at least two times now. Readers do not know the reason for the flag, but I guess, this will not happen with spam? Might even spare moderators some critique, they are not so much anonymous, &c.
Ok, makes sense now as suggestion! However, is it a feature that Discourse have and just need to be enabled in OSM instance?
Because, if it is feature request for Discourse, it should probably be submitted at https://meta.discourse.org/ instead.