I don't know why choice of language is having such sway in determining what you view as professional. Maybe it's just a cultural difference but where I'm from people just use the words they need to to communicate what they're trying to say. If something's a shit show I'd prefer someone just said it rather than dancing around it with corpo-speak.
As someone from a cultural background that is considered very direct and blunt, I can say that there is a rather fine line between being direct and being an asshole.
This post devolves into a personal attack one sentence in. There was no reason to go into Jared's life at all to begin with. The entire post doesn't need to exist at all if you're confident that Bun leaving will have zero or even positive impact. Why turn an already negative event of a slop rewrite into drama? It's petty and immature.
> I don't know why choice of language is having such sway in determining what you view as professional
This is a blog post: it's purely textual, language is the only thing it uses to convey meaning. The words chosen to do so reflect what the author thinks.
> where I'm from people just use the words they need to to communicate what they're trying to say
Yes. What ark is trying to say, via the words he chose, is what's earning him the description of "unprofessional".
He could say every factual thing in the blog post without being unprofessional, he just chose not to.