Mob Teams Fail to Affect Behavior

Mobs are not affected by teams.

What I expected to happen was for the mobs to not kill players on the same team and fight mobs on enemy teams.

Only Shulkers did so. They are the only mob affected by being on a team.

Steps to Reproduce:
1. Put any mob but a shulker on a team
2. Join that team
3. Get attacked by the mob.