Checking if the attacked entity has a tag

Hey, I wanted to check if the entity the player has attacked has the hostile_entity tag. But it activates for every entity:
{
  "criteria": {
    "requirement": {
      "trigger": "minecraft:player_hurt_entity",
      "conditions": {
        "damage": {
          "type": {
            "source_entity": {}
          }
        },
        "damaged": {
          "tag": "hostile_entity"
        }
      }
    }
  },
  "rewards": {
    "function": "immersive_combat:start_combat"
  }
}

What is wrong here?