The rules (such as they are):
The mods retain the right to move posts about and to ban anyone seen as a nuisance. Posts are not edited or blocked or deleted*; it's opaque as a benefit** and requires too much work (and requires a gordian knot of definitions as to what is and isn't crossing the line, which just favors people who know how to be an ass within the lines), and I'd rather just be rid of characters who don't seem to have any genuine historical interest in the subjects under discussion.
* Excepting spam, of course.
** Compared to the pretty clear benefit of feeling certain of what people have posted to the forum, in their own words (forum history, so to speak).
If you want to know about the kind of stuff that can make mods lose patience with posters, try sorting through the posts of the already banned
"... almost every critical biblical position was earlier advanced by skeptics." - Raymond Brown