Christians do not believe they worship a "person" per se; or, rather, not merely a person. They worship a Trinity, who they regard as 3 persons/personalities, of one being; one of those 3 persons happens to be the Incarnation.
IMO, deified monarchs are not SMA. Christianity did not deify any monarchs during the Medieval period. Deification of leaders did occur in the Roman period, and arguably some absolutist monarchs may have been making a run for it, but deification of rulers just wasn't typical of any part of Medieval Europe. Really, I'm struggling to think of any instance after, say, 500 AD where a person was deified. The closest I can think of is declaring someone a Saint.
IMO, an anti-religion isn't okay. You can be against a religion. But founding a BM religion as an anti-religion is obviously metagaming. It's not an SMA issue, it's a "You're abusing the feature" issue.
