The check giving this error is pretty old, so it seems that you got it to work was not intentional: https://github.com/LemmyNet/lemmy/blame/63d3759c481ff2d7594d391ae86e881e2aeca56d/crates/api_common/src/utils.rs#L539
As far as I can see, 0.18 and its release candidates only added additional checks preventing such an instance to be set up in the first place.
I’m not sure what exactly you’re asking, but I’ll assume it’s not the standard “I can’t find this remote community” question, as your fourth search result is from the exact community you’re searching for… and has a direct clickable link to the community as federated to your instance (in green).
If you want a direct link as a search result to the community, search for it’s URL on its home instance, e.g. here https://lemmy.ml/c/lemmy_support
You can get this via the link under the community header on the left, where it says “Lemmy Support” and underneath has the hyperlink “!lemmy_support@lemmy.ml”. Click that link or copy its URL.
It has nothing to with you having to accept it, it’s the instance itself having to confirm the subscription request. That doesn’t work reliably atm: https://github.com/LemmyNet/lemmy/issues/3203
I was thinking of something like that too, but probably never would’ve gotten around to implement it myself, so thanks! Could you put your script on Github or something maybe?
Also it would be great if it could copy at least top-level comments by OP, because that’s often used for linking to a source.
Yes, that’s what this check (and the later introduced changes) are meant for. On the reasoning why this configuration is not desired I can’t comment.