In the case at hand, Matthew would have had to at some point represent himself as supporting slowing down or stopping AI progress. For at least the past 2.5 years, he has been arguing against doing that in extreme depth on the public internet. So I don’t really see how you can interpret him starting a company that aims to speed up AI as inconsistent with his publicly stated views, which seems like a necessary condition for him to be a “traitor”. If Matthew had previously claimed to be a pause AI guy, then I think it would be more reasonable for other adherents of that view to call him a “traitor.” I don’t think that’s raising the definitional bar so high that no will ever meet it—it seems like a very basic standard.
I have no idea how to interpret “sellout” in this context, as I have mostly heard that term used for such situations as rappers making washing machine commercials. Insofar as I am familiar with that word, it seems obviously inapplicable.
Can you be a bit more specific about what it means for the EA community to deny Matthew (and Mechanize) implicit support, and which ways of doing this you would find reasonable vs. unreasonable?