It's been a thing for a while, he just gradually became louder and more brave about it as it became more and more accepted to be public about it (see DHH, Garry Tan, Palantir, etc). A lot of smart people inside Vercel saw the writing on the wall and left.

Wait, sorry - what’s the controversy regarding DHH? Others don’t surprise me.

Several recent attempts at hard forking rails, https://tekin.co.uk/2025/09/the-ruby-community-has-a-dhh-pro...

Due to just the most recent DHH tirade, but a similarly long trend as with Guillermo: https://world.hey.com/dhh/as-i-remember-london-e7d38e64

Wow, I missed that one. That is a truly bizarre post.