I disagree with this. Relationships with Cluster-B people can become very dangerous. This can even include parent-child relationships, for example, if the parent has NPD (narcisstic personality disorder). At the end you really need to look out for yourself and your mental health first (hence not at any cost).

"but _some_ are holy and must be salvaged at any cost"

My relationship with my mother is part of that "some" for me. For others it may be someone else, but I didn't say everyone needs to salvage relationships with their parents at all, I shared my personal experience.

Hopefully everyone has a relationship worth saving. Find that and fight for it, because a good relationship is worth any cost, up to including your life (eg. relationship with your child).

I'm not an expert but does your way of thinking about this not map to Cluster-B personality types?