Offending mod: It Takes a Pillage
Config variable: REPLACE_IRON_GOLEMS
File: https://github.com/izofar/takes-a-pillage/blob/efea3d108053ad4b2f609ddb27f7592d75209cbf/src/main/java/com/izofar/takesapillage/event/ModEntityEvents.java

Reasoning: basically impossible to create iron golem farm, which is more useful than being able to repair clay golems with clay balls.