Maybe it was too much, but one counterpoint: if horrible managers never get called out how are you supposed to know to avoid them / how will they face consequences?

I understand authors frustration, I've experienced the same in the past but could not voice this beyond just some close friends and coworkers (who knew it already anyway), for fear of repercussions. I've since left but of course this person remains, and from what I hear is still as bad.

Outsiders might join that organization unaware of this. Others working with those teams might not know this and can get burned by it.

Was this particular call out justified? I don't know. But I don't think it is inherently bad.