I agree with the spirit of what you're saying: that many aspects of this post seem unnecessary. But I do think there are reasonable answers to your (admittedly probably rhetorical) questions.

Zig is a relatively young language with a small community, and Oven/Bun is one of few places that someone could previously have written Zig code professionally. It's therefore Zig's business to make sure that either it's a good place to refer community members for work, or that they don't explicitly encourage people to work there. Likewise, as one of the highest-profile Zig projects, the community's leaders were understandably invested in making sure it represented the language well.

I feel like I am exactly the target audience for this post: someone who uses Zig regularly, but hasn't touched Bun, despite being aware of it. While I would have proceeded differently than Andrew Kelley here in terms of framing and phrasing (and leaving out some parts entirely), I do think reading this gave me new information about Zig's relationship to Bun. The specific dry, professional post you suggest wouldn't have given me any new information at all.