subject the community is dedicated to
Following the title of the community and its description, I (and apparently other people as well) got the distinct impression this subject to be "alternative urban mobility".
I now understand that it is a fan-community for some bike-influencer instead?
This came as somewhat of a surprise, as there are no obvious indications for it.
And, btw, the gatekeeping didn't help.
Thanks.
The second part is finally a very good example for a reply that is not gatekeeping but actually helpful.
Would perhaps be a good idea to have that exact paragraph be put at the top of the community description.
And regarding the first part:
If stumbling across a post linking to inaccessible content in any community:
Instant reaction will always be leaving a "Paywalled" or similar comment.
That's just basic netiquette to inform other users and give the OP a hint that he might want to do something about it.