I agree that ap-next is not a fork, and might have stayed on that website. That said I don't think there's deeper politics to this removal, just that the links on the site are rather arbitrary and in need of good curation. E.g. fedify is nice to mention, but also just but one such project where there are multiple.
The entire online presence of SWICG/SocialCG including the AP.rocks website are a mess that almost seems designed to discourage ecosystem participants.
It saddens me as 3 years ago, when AP.rocks was still considered to be part of SocialHub, I had a whole initiative prepared to once and for all create a great developer portal at this domain name.
https://socialhub.activitypub.rocks/t/activitypub-rocks-portal-from-standards-movement-to-grassroots-fedi/3577
In particular that top-level aggregator site would need to serve as an entry point to drill down into the entire grassroots ecosystem, help people find their way around..
https://socialhub.activitypub.rocks/t/ideating-organization-structure-for-the-grassroots-fediverse-wiki/3037
The SWICG took over that initiative without consultation, and then let it languish.