1. "Pilot error" is a subset of "human error". There is no other distinction between the two terms.
2. "Pilot error" is indeed a mechanism for accidents, although it is not a cause.
3. Acknowledging error is not equivalent to assigning blame.
There's nothing wrong with the term "pilot error", as long as it's not listed in "probable cause" statements. Let's not misrepresent the pioneering and important work done by Reason and others; their work is about the nature of error, not about some PC humbug that forbids you to call things by their right names.
"aircraft only bite fools" vs. "aircraft only bite you if you do something foolish" -- equivalent if, but only if, only fools do foolish things (not the case)