When you set the universalAnger gamemode to true, llamas won't spit at players that hurt them. Hostile mobs that hurt llamas still cause llamas to spit at them however.

To reproduce

1. /gamemode survival @s
2. /summon minecraft:llama ~ ~ ~
3. /gamerule universalAnger true
4. Hit the llama
   → Notice how it doesn't spit or even target you