For me, it's social dancing, specifically West Coast Swing. Because while there is just social dancing, and some who only do it, there's a bit of a culture of competition, and it has its own governing body for determining where you place in competitions, and when it does sound like a cult when described.
In my experience, modern demonic black magic has a much more beginner-friendly community with less gatekeeping.
Modern demonic black magic is called "investing."
Look, we may consort with damned beings whose twisted souls know nothing but hunger, but we're at least principled about it.