shulkers spawn in peaceful mode?

shulkers spawn in peaceful mode.

i expected that there a hostile mob cause they lift you in the air. they attack for no reason.

they should not spawn in peaceful mode because there hostile.

they spawned in peaceful mode.
i was testing with the mob spawners and then i put a shulker in the spawner. well then i didnt want a lot of mobs to spawn (because i also had other mob spawners in there to) so i switched to peaceful. then they still spawned. so are the shulkers hostile or not?

Steps to Reproduce:
1. do /give @p mob_spawner
2. get a shulker egg
3. then right click the spawner.
4. then put your mode to peaceful.
5. then just wait.