In medicine there is the concept of a disease being “subclinical”, and I think the concept can apply to bullying in the workplace.
Every workplace has a threshold for bad behaviour, and subclinical bullying is bad behaviour which doesn’t cross the threshold. Much like how a doctor often won’t treat a subclinical disease, your manager often won’t address subclinical bullying. There are lots of reasons why this might be the case, for better or for worse. One of those reasons might be that your manager is showing grace, which can feel unfair, but is also important for a healthy team dynamic.