"Disbelief or lack of belief"...oh my...so I need to revise my chart to read "theist" and "anti-theist". And 95% of everyone, myself included, needs to stop misusing the term "atheist". As a scientifically minded person, I shall update my schema in the face of evidence which contradicts it.
So what tf is agnosticism then anyway? An archaic euphemism for atheist? To your point, it's probably a sub-set of atheism. Lol, labels