Aaron,

You are correct it would have been better for them to just politely reject your essay in some anodyne way and move on. They made it a point to highlight they were cancelling you (although they probably don't see it precisely in that way, even though it was) for some perceived offense on your part. It was a clumsy attempt to be on the moral high ground.

Since the original essay has been removed from Arc Digital, it's not possible to evaluate it for what possible objection it engendered. It must have been something really insidious if it was responsible for them not being able to get the range of contributors they wanted because of it! Or not. I find perceptions of scale, relative importance, and proportionality are often highly skewed (and self-importance massively inflated) in academic environments.