The argument isn't to avoid calling out "bad" behaviour, it's that you can do so with a professional (or at least not actively childish) tone. Using phrases like "stinky manager" while taking multiple jabs at Jarred's personal and educational background (implying by not going to university he was too stupid to think critically about his path forward) paints a weirdly childish yet elitist viewpoint. The blog post reads as vindictive, akin to something along the lines of "screw you kid, glad to be rid of you, and thanks for the $120,000 btw."

I don't interact with Zig or Bun, but I certainly haven't been enticed to try Zig after this.