lemmy.ml has changed their level of transparency about their political leanings twice. Look at the history of their home page description:
April 2021 to June 2021:
The flagship instance of lemmy.
June 2021 to November 2022:
A community of leftist privacy and FOSS enthusiasts, run by Lemmy’s developers
November 2022 to now:
A community of privacy and FOSS enthusiasts, run by Lemmy’s developers
Your conspiracy theory accusing Meta of being responsible for lemmy.world users wanting to defederate from lemmy.ml is ridiculous. Nobody forced lemmy.ml moderators to block people who criticize China, Russia, or Marxism-Leninism from all of their communities.
These lemmy.ml moderators made these bad choices all by themselves without Meta’s help, and lemmy.world has the right to exclude those communities through defederation so that no lemmy.world user has to worry about whether their comment to a front page post goes against a lemmy.ml moderator’s political ideology.