Yeah, I was also feeling cheated that they are stealing our meme.

But I guess it's really an independent innovation, and actually a different idea. NPCs in games have several different properties, so if you use them as a metaphor it can mean different things, and the meaning of the meme naturally morphs.

In the original LW article from 2013 (https://www.greaterwrong.com/posts/cenSWez9Ddgsjd5Fc/to-what-degree-do-you-model-people-as-agents), Swimmer963 actually talked about several different things:

1. being problematic for solipsism (i.e., having a subjective experience)
2. being conscientious/agenty
3. being morally blameworthy/praiseworthy

and it's not at all clear that these should coincide. The sense that Yudkowsky picked up and used is (2).

When /v/ invented the idea in 2016 (https://knowyourmeme.com/memes/npc-wojak), it was as a comment to a study about how often people have internal monologues, so it's really in sense (1). But someone could have no internal experience and still be agently, e.g. think of the Scramblers in Blindsight.

Finally, the more recent use of the meme (https://www.nytimes.com/2018/10/16/us/politics/npc-twitter-ban.html) seems to focus on

4. repeating a small scripted dialog