"I'm not even an atheist so much as I am an antitheist; I not only maintain that all religions are versions of the same untruth, but I hold that the influence of churches, and the effect of religious belief, is positively harmful." - C. H.

I mean I feel like that's less of a belief about theism, and more of a stance on the specific issue of theism being harmful or not. As an anti-theist myself, I think my anti-theism is sort of a byproduct of the fact that I am a non-theist. If that makes sense. Like if someone asked me "Do you believe in god?" I probably wouldn't start with "I believe religion is harmful to society" cuz that's technically not an answer to the question. Maybe I'm wrong about that tho, but that's what I always felt.

Yes

I had never classified myself as one before, but I suppose I probably should.

I added it myself.