Now we're at the crux of it. If you believe NPCs can be griefers, than your beef isn't with other players - it's with the game gods who designed it. It's a disconnect from the reality of video games of the highest order. To illustrate, consider a simpler game of old...would you acknowledge that it would be just a little silly to call the descending aliens in Space Invaders to be "griefers"? Does "griefer" now have so little meaning that the mere presence of ANY antagonist is triggering?
Space Invaders: No, not in the slightest. Their behavior was purely mindless, completely predictable, and did not attempt to emulate human behavior.
In later games, with more advanced attempts at AI, you might encounter enemies who would use the Lamest Possible Tactic, such as standing directly above you and repeatedly striking making annoying or difficult to regain your feet. This might be some of the earliest attempts to emulate what could be called "Griefing".
Your choice to use the term "triggering", a disgusting millennial cry-phrase that should be struck from human parlance, urges me to discontinue discourse, but I will forge ahead. The term "Griefer" still has the same denotation - that which causes undue or excessive hardship (grief) for no other purpose except to cause hardship (grief).
Establishing a threshold of what is "undue" or "excessive", however, requires a level of subjective interpretation. For you, spending a weekend on an uninhabited, tropical island, with nothing more than knife and a banana hammock might be "undue" or "excessive" to you, but a welcome and relaxing stay for me.