Clerics, Blunt Weapons, and Christian Assumptions
One items which received a lot of humor back in its day was the restriction of clerics only being able to use blunt weapons as they were forbidden from using weapons which shed blood. Anyone who has seen a medieval mace knows that a solid hit with one of those is going to shed a lot of blood, blunt weapon or not.
Recently I was reading Barbara Tuchman's A Distant Mirror: The Calamitous 14th Century. It included the following statement:
[The knight] also had available, either attached tio his saddle or carried by his squire, a longer sword for thrusting like a lance, a battle-ax fitted with a spike behind the curving blade, and a club-headed mace with sharpened, ridged edges, a weapon favored by martial bishops and abbots on the theory it did not come under the rule forbidding clerics "to smite with the edge of the sword."
This work is copyrighted 1978 so it was clearly not the actual source for the rule regarding clerics but it clearly does represent the reasoning used for a cleric's weapon restriction. I'm not certain if this is "true" or not - I've done some Googling and have seen people who do not feel there was any such restriction but either way there are clearly sources that support this restriction that Gygax and company must have encountered.