Iron golem attacking players on peaceful difficulty, but attack does not hurt player

Steps to reproduce:

1. Set the difficulty to peaceful (/difficulty 0)

2. Summon an iron golem (/summon VillagerGolem)

3. Make sure you're in Survival mode (/gamemode 0)

4. Attack the golem

5. The golem will repeatedly swing its arms at you, but you won't receive any damage or knockback

I would expect the golem to either deal damage or not swing its arms at all.