Managers are responsible for the context that their team operates within. The context, or culture, is a reflection of the manager's response to what goes on in the workplace, whether good or bad.

This is not to say the manager necessarily creates the toxicity themselves, but if they do not address it - do not seek to create the most effective context - the blame for the toxicity falls to them.

The author here points out some ways to deal with this, primarily communication. Sometimes the first step is to look into the mirror to find the genesis of something like a toxic work environment.