I don't know, either. Maybe we could post in GT and ask the Administrator who posted the new rule to explain.
ISTM, many Christians do conflate the assumptions of classical theism with the scriptures and the creeds. For example, if we say, "I believe in one God, the Father almighty..." this must mean "almighty" entails certain things, like all the "omnis" of classical theism. But neither the scriptures nor the creeds demand such a definition of "almighty."
Open theism actually does not conflict with the usual definition of "almighty," as far as I can see. It does conflict with the usual definition of omniscience, but omniscience does not appear anywhere in the Nicene Creed.
Should we invite Flesh99 to explain?