Programming is a form of communication. When you develop a piece of software, it will intrinsically be biased to boost the kinds of messages you believe in. This is both because you as a person think about problems a certain way, and because the code you write is meant to convey to others how you were thinking about the problem you were trying to solve. Who heads projects and how they communicate with their community matters to what the product produced will become, not just because of how the leads will think about the problem, but also because people who don't get along with them won't wind up contributing. Beehaw requested moderation tools that the lead lemmy Devs didn't view as valuable. The result is beehaw, reasonably, gave up on getting PRs merged and issues tracked in the issue tracker, instead choosing to look at Sublinks which was explicitly started in response to Lemmy's devs not behaving well with their own development community.
And for anyone saying Sublinks is splintering the Lemmy Dev community, no, lemmy's devs did that themselves